File: | llvm/lib/CodeGen/BranchFolding.cpp |
Warning: | line 1495, column 11 Forming reference to null pointer |
Press '?' to see keyboard shortcuts
Keyboard shortcuts:
1 | //===- BranchFolding.cpp - Fold machine code branch instructions ----------===// | ||||||||
2 | // | ||||||||
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||||||||
4 | // See https://llvm.org/LICENSE.txt for license information. | ||||||||
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||||||||
6 | // | ||||||||
7 | //===----------------------------------------------------------------------===// | ||||||||
8 | // | ||||||||
9 | // This pass forwards branches to unconditional branches to make them branch | ||||||||
10 | // directly to the target block. This pass often results in dead MBB's, which | ||||||||
11 | // it then removes. | ||||||||
12 | // | ||||||||
13 | // Note that this pass must be run after register allocation, it cannot handle | ||||||||
14 | // SSA form. It also must handle virtual registers for targets that emit virtual | ||||||||
15 | // ISA (e.g. NVPTX). | ||||||||
16 | // | ||||||||
17 | //===----------------------------------------------------------------------===// | ||||||||
18 | |||||||||
19 | #include "BranchFolding.h" | ||||||||
20 | #include "llvm/ADT/BitVector.h" | ||||||||
21 | #include "llvm/ADT/DenseMap.h" | ||||||||
22 | #include "llvm/ADT/STLExtras.h" | ||||||||
23 | #include "llvm/ADT/SmallPtrSet.h" | ||||||||
24 | #include "llvm/ADT/SmallSet.h" | ||||||||
25 | #include "llvm/ADT/SmallVector.h" | ||||||||
26 | #include "llvm/ADT/Statistic.h" | ||||||||
27 | #include "llvm/Analysis/ProfileSummaryInfo.h" | ||||||||
28 | #include "llvm/CodeGen/Analysis.h" | ||||||||
29 | #include "llvm/CodeGen/LivePhysRegs.h" | ||||||||
30 | #include "llvm/CodeGen/MachineBasicBlock.h" | ||||||||
31 | #include "llvm/CodeGen/MachineBlockFrequencyInfo.h" | ||||||||
32 | #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" | ||||||||
33 | #include "llvm/CodeGen/MachineFunction.h" | ||||||||
34 | #include "llvm/CodeGen/MachineFunctionPass.h" | ||||||||
35 | #include "llvm/CodeGen/MachineInstr.h" | ||||||||
36 | #include "llvm/CodeGen/MachineInstrBuilder.h" | ||||||||
37 | #include "llvm/CodeGen/MachineJumpTableInfo.h" | ||||||||
38 | #include "llvm/CodeGen/MachineLoopInfo.h" | ||||||||
39 | #include "llvm/CodeGen/MachineModuleInfo.h" | ||||||||
40 | #include "llvm/CodeGen/MachineOperand.h" | ||||||||
41 | #include "llvm/CodeGen/MachineRegisterInfo.h" | ||||||||
42 | #include "llvm/CodeGen/MachineSizeOpts.h" | ||||||||
43 | #include "llvm/CodeGen/TargetInstrInfo.h" | ||||||||
44 | #include "llvm/CodeGen/TargetOpcodes.h" | ||||||||
45 | #include "llvm/CodeGen/TargetPassConfig.h" | ||||||||
46 | #include "llvm/CodeGen/TargetRegisterInfo.h" | ||||||||
47 | #include "llvm/CodeGen/TargetSubtargetInfo.h" | ||||||||
48 | #include "llvm/IR/DebugInfoMetadata.h" | ||||||||
49 | #include "llvm/IR/DebugLoc.h" | ||||||||
50 | #include "llvm/IR/Function.h" | ||||||||
51 | #include "llvm/InitializePasses.h" | ||||||||
52 | #include "llvm/MC/LaneBitmask.h" | ||||||||
53 | #include "llvm/MC/MCRegisterInfo.h" | ||||||||
54 | #include "llvm/Pass.h" | ||||||||
55 | #include "llvm/Support/BlockFrequency.h" | ||||||||
56 | #include "llvm/Support/BranchProbability.h" | ||||||||
57 | #include "llvm/Support/CommandLine.h" | ||||||||
58 | #include "llvm/Support/Debug.h" | ||||||||
59 | #include "llvm/Support/ErrorHandling.h" | ||||||||
60 | #include "llvm/Support/raw_ostream.h" | ||||||||
61 | #include "llvm/Target/TargetMachine.h" | ||||||||
62 | #include <cassert> | ||||||||
63 | #include <cstddef> | ||||||||
64 | #include <iterator> | ||||||||
65 | #include <numeric> | ||||||||
66 | #include <vector> | ||||||||
67 | |||||||||
68 | using namespace llvm; | ||||||||
69 | |||||||||
70 | #define DEBUG_TYPE"branch-folder" "branch-folder" | ||||||||
71 | |||||||||
72 | STATISTIC(NumDeadBlocks, "Number of dead blocks removed")static llvm::Statistic NumDeadBlocks = {"branch-folder", "NumDeadBlocks" , "Number of dead blocks removed"}; | ||||||||
73 | STATISTIC(NumBranchOpts, "Number of branches optimized")static llvm::Statistic NumBranchOpts = {"branch-folder", "NumBranchOpts" , "Number of branches optimized"}; | ||||||||
74 | STATISTIC(NumTailMerge , "Number of block tails merged")static llvm::Statistic NumTailMerge = {"branch-folder", "NumTailMerge" , "Number of block tails merged"}; | ||||||||
75 | STATISTIC(NumHoist , "Number of times common instructions are hoisted")static llvm::Statistic NumHoist = {"branch-folder", "NumHoist" , "Number of times common instructions are hoisted"}; | ||||||||
76 | STATISTIC(NumTailCalls, "Number of tail calls optimized")static llvm::Statistic NumTailCalls = {"branch-folder", "NumTailCalls" , "Number of tail calls optimized"}; | ||||||||
77 | |||||||||
78 | static cl::opt<cl::boolOrDefault> FlagEnableTailMerge("enable-tail-merge", | ||||||||
79 | cl::init(cl::BOU_UNSET), cl::Hidden); | ||||||||
80 | |||||||||
81 | // Throttle for huge numbers of predecessors (compile speed problems) | ||||||||
82 | static cl::opt<unsigned> | ||||||||
83 | TailMergeThreshold("tail-merge-threshold", | ||||||||
84 | cl::desc("Max number of predecessors to consider tail merging"), | ||||||||
85 | cl::init(150), cl::Hidden); | ||||||||
86 | |||||||||
87 | // Heuristic for tail merging (and, inversely, tail duplication). | ||||||||
88 | // TODO: This should be replaced with a target query. | ||||||||
89 | static cl::opt<unsigned> | ||||||||
90 | TailMergeSize("tail-merge-size", | ||||||||
91 | cl::desc("Min number of instructions to consider tail merging"), | ||||||||
92 | cl::init(3), cl::Hidden); | ||||||||
93 | |||||||||
94 | namespace { | ||||||||
95 | |||||||||
96 | /// BranchFolderPass - Wrap branch folder in a machine function pass. | ||||||||
97 | class BranchFolderPass : public MachineFunctionPass { | ||||||||
98 | public: | ||||||||
99 | static char ID; | ||||||||
100 | |||||||||
101 | explicit BranchFolderPass(): MachineFunctionPass(ID) {} | ||||||||
102 | |||||||||
103 | bool runOnMachineFunction(MachineFunction &MF) override; | ||||||||
104 | |||||||||
105 | void getAnalysisUsage(AnalysisUsage &AU) const override { | ||||||||
106 | AU.addRequired<MachineBlockFrequencyInfo>(); | ||||||||
107 | AU.addRequired<MachineBranchProbabilityInfo>(); | ||||||||
108 | AU.addRequired<ProfileSummaryInfoWrapperPass>(); | ||||||||
109 | AU.addRequired<TargetPassConfig>(); | ||||||||
110 | MachineFunctionPass::getAnalysisUsage(AU); | ||||||||
111 | } | ||||||||
112 | }; | ||||||||
113 | |||||||||
114 | } // end anonymous namespace | ||||||||
115 | |||||||||
116 | char BranchFolderPass::ID = 0; | ||||||||
117 | |||||||||
118 | char &llvm::BranchFolderPassID = BranchFolderPass::ID; | ||||||||
119 | |||||||||
120 | INITIALIZE_PASS(BranchFolderPass, DEBUG_TYPE,static void *initializeBranchFolderPassPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Control Flow Optimizer" , "branch-folder", &BranchFolderPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<BranchFolderPass>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeBranchFolderPassPassFlag; void llvm::initializeBranchFolderPassPass (PassRegistry &Registry) { llvm::call_once(InitializeBranchFolderPassPassFlag , initializeBranchFolderPassPassOnce, std::ref(Registry)); } | ||||||||
121 | "Control Flow Optimizer", false, false)static void *initializeBranchFolderPassPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Control Flow Optimizer" , "branch-folder", &BranchFolderPass::ID, PassInfo::NormalCtor_t (callDefaultCtor<BranchFolderPass>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeBranchFolderPassPassFlag; void llvm::initializeBranchFolderPassPass (PassRegistry &Registry) { llvm::call_once(InitializeBranchFolderPassPassFlag , initializeBranchFolderPassPassOnce, std::ref(Registry)); } | ||||||||
122 | |||||||||
123 | bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) { | ||||||||
124 | if (skipFunction(MF.getFunction())) | ||||||||
125 | return false; | ||||||||
126 | |||||||||
127 | TargetPassConfig *PassConfig = &getAnalysis<TargetPassConfig>(); | ||||||||
128 | // TailMerge can create jump into if branches that make CFG irreducible for | ||||||||
129 | // HW that requires structurized CFG. | ||||||||
130 | bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() && | ||||||||
131 | PassConfig->getEnableTailMerge(); | ||||||||
132 | MBFIWrapper MBBFreqInfo( | ||||||||
133 | getAnalysis<MachineBlockFrequencyInfo>()); | ||||||||
134 | BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true, MBBFreqInfo, | ||||||||
135 | getAnalysis<MachineBranchProbabilityInfo>(), | ||||||||
136 | &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI()); | ||||||||
137 | auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>(); | ||||||||
138 | return Folder.OptimizeFunction( | ||||||||
139 | MF, MF.getSubtarget().getInstrInfo(), MF.getSubtarget().getRegisterInfo(), | ||||||||
140 | MMIWP ? &MMIWP->getMMI() : nullptr); | ||||||||
141 | } | ||||||||
142 | |||||||||
143 | BranchFolder::BranchFolder(bool defaultEnableTailMerge, bool CommonHoist, | ||||||||
144 | MBFIWrapper &FreqInfo, | ||||||||
145 | const MachineBranchProbabilityInfo &ProbInfo, | ||||||||
146 | ProfileSummaryInfo *PSI, | ||||||||
147 | unsigned MinTailLength) | ||||||||
148 | : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength), | ||||||||
149 | MBBFreqInfo(FreqInfo), MBPI(ProbInfo), PSI(PSI) { | ||||||||
150 | if (MinCommonTailLength == 0) | ||||||||
151 | MinCommonTailLength = TailMergeSize; | ||||||||
152 | switch (FlagEnableTailMerge) { | ||||||||
153 | case cl::BOU_UNSET: EnableTailMerge = defaultEnableTailMerge; break; | ||||||||
154 | case cl::BOU_TRUE: EnableTailMerge = true; break; | ||||||||
155 | case cl::BOU_FALSE: EnableTailMerge = false; break; | ||||||||
156 | } | ||||||||
157 | } | ||||||||
158 | |||||||||
159 | void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) { | ||||||||
160 | assert(MBB->pred_empty() && "MBB must be dead!")((MBB->pred_empty() && "MBB must be dead!") ? static_cast <void> (0) : __assert_fail ("MBB->pred_empty() && \"MBB must be dead!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 160, __PRETTY_FUNCTION__)); | ||||||||
161 | LLVM_DEBUG(dbgs() << "\nRemoving MBB: " << *MBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nRemoving MBB: " << *MBB; } } while (false); | ||||||||
162 | |||||||||
163 | MachineFunction *MF = MBB->getParent(); | ||||||||
164 | // drop all successors. | ||||||||
165 | while (!MBB->succ_empty()) | ||||||||
166 | MBB->removeSuccessor(MBB->succ_end()-1); | ||||||||
167 | |||||||||
168 | // Avoid matching if this pointer gets reused. | ||||||||
169 | TriedMerging.erase(MBB); | ||||||||
170 | |||||||||
171 | // Update call site info. | ||||||||
172 | std::for_each(MBB->begin(), MBB->end(), [MF](const MachineInstr &MI) { | ||||||||
173 | if (MI.shouldUpdateCallSiteInfo()) | ||||||||
174 | MF->eraseCallSiteInfo(&MI); | ||||||||
175 | }); | ||||||||
176 | // Remove the block. | ||||||||
177 | MF->erase(MBB); | ||||||||
178 | EHScopeMembership.erase(MBB); | ||||||||
179 | if (MLI) | ||||||||
180 | MLI->removeBlock(MBB); | ||||||||
181 | } | ||||||||
182 | |||||||||
183 | bool BranchFolder::OptimizeFunction(MachineFunction &MF, | ||||||||
184 | const TargetInstrInfo *tii, | ||||||||
185 | const TargetRegisterInfo *tri, | ||||||||
186 | MachineModuleInfo *mmi, | ||||||||
187 | MachineLoopInfo *mli, bool AfterPlacement) { | ||||||||
188 | if (!tii) return false; | ||||||||
189 | |||||||||
190 | TriedMerging.clear(); | ||||||||
191 | |||||||||
192 | MachineRegisterInfo &MRI = MF.getRegInfo(); | ||||||||
193 | AfterBlockPlacement = AfterPlacement; | ||||||||
194 | TII = tii; | ||||||||
195 | TRI = tri; | ||||||||
196 | MMI = mmi; | ||||||||
197 | MLI = mli; | ||||||||
198 | this->MRI = &MRI; | ||||||||
199 | |||||||||
200 | UpdateLiveIns = MRI.tracksLiveness() && TRI->trackLivenessAfterRegAlloc(MF); | ||||||||
201 | if (!UpdateLiveIns) | ||||||||
202 | MRI.invalidateLiveness(); | ||||||||
203 | |||||||||
204 | // Fix CFG. The later algorithms expect it to be right. | ||||||||
205 | bool MadeChange = false; | ||||||||
206 | for (MachineBasicBlock &MBB : MF) { | ||||||||
207 | MachineBasicBlock *TBB = nullptr, *FBB = nullptr; | ||||||||
208 | SmallVector<MachineOperand, 4> Cond; | ||||||||
209 | if (!TII->analyzeBranch(MBB, TBB, FBB, Cond, true)) | ||||||||
210 | MadeChange |= MBB.CorrectExtraCFGEdges(TBB, FBB, !Cond.empty()); | ||||||||
211 | } | ||||||||
212 | |||||||||
213 | // Recalculate EH scope membership. | ||||||||
214 | EHScopeMembership = getEHScopeMembership(MF); | ||||||||
215 | |||||||||
216 | bool MadeChangeThisIteration = true; | ||||||||
217 | while (MadeChangeThisIteration) { | ||||||||
218 | MadeChangeThisIteration = TailMergeBlocks(MF); | ||||||||
219 | // No need to clean up if tail merging does not change anything after the | ||||||||
220 | // block placement. | ||||||||
221 | if (!AfterBlockPlacement || MadeChangeThisIteration) | ||||||||
222 | MadeChangeThisIteration |= OptimizeBranches(MF); | ||||||||
223 | if (EnableHoistCommonCode) | ||||||||
224 | MadeChangeThisIteration |= HoistCommonCode(MF); | ||||||||
225 | MadeChange |= MadeChangeThisIteration; | ||||||||
226 | } | ||||||||
227 | |||||||||
228 | // See if any jump tables have become dead as the code generator | ||||||||
229 | // did its thing. | ||||||||
230 | MachineJumpTableInfo *JTI = MF.getJumpTableInfo(); | ||||||||
231 | if (!JTI) | ||||||||
232 | return MadeChange; | ||||||||
233 | |||||||||
234 | // Walk the function to find jump tables that are live. | ||||||||
235 | BitVector JTIsLive(JTI->getJumpTables().size()); | ||||||||
236 | for (const MachineBasicBlock &BB : MF) { | ||||||||
237 | for (const MachineInstr &I : BB) | ||||||||
238 | for (const MachineOperand &Op : I.operands()) { | ||||||||
239 | if (!Op.isJTI()) continue; | ||||||||
240 | |||||||||
241 | // Remember that this JT is live. | ||||||||
242 | JTIsLive.set(Op.getIndex()); | ||||||||
243 | } | ||||||||
244 | } | ||||||||
245 | |||||||||
246 | // Finally, remove dead jump tables. This happens when the | ||||||||
247 | // indirect jump was unreachable (and thus deleted). | ||||||||
248 | for (unsigned i = 0, e = JTIsLive.size(); i != e; ++i) | ||||||||
249 | if (!JTIsLive.test(i)) { | ||||||||
250 | JTI->RemoveJumpTable(i); | ||||||||
251 | MadeChange = true; | ||||||||
252 | } | ||||||||
253 | |||||||||
254 | return MadeChange; | ||||||||
255 | } | ||||||||
256 | |||||||||
257 | //===----------------------------------------------------------------------===// | ||||||||
258 | // Tail Merging of Blocks | ||||||||
259 | //===----------------------------------------------------------------------===// | ||||||||
260 | |||||||||
261 | /// HashMachineInstr - Compute a hash value for MI and its operands. | ||||||||
262 | static unsigned HashMachineInstr(const MachineInstr &MI) { | ||||||||
263 | unsigned Hash = MI.getOpcode(); | ||||||||
264 | for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { | ||||||||
265 | const MachineOperand &Op = MI.getOperand(i); | ||||||||
266 | |||||||||
267 | // Merge in bits from the operand if easy. We can't use MachineOperand's | ||||||||
268 | // hash_code here because it's not deterministic and we sort by hash value | ||||||||
269 | // later. | ||||||||
270 | unsigned OperandHash = 0; | ||||||||
271 | switch (Op.getType()) { | ||||||||
272 | case MachineOperand::MO_Register: | ||||||||
273 | OperandHash = Op.getReg(); | ||||||||
274 | break; | ||||||||
275 | case MachineOperand::MO_Immediate: | ||||||||
276 | OperandHash = Op.getImm(); | ||||||||
277 | break; | ||||||||
278 | case MachineOperand::MO_MachineBasicBlock: | ||||||||
279 | OperandHash = Op.getMBB()->getNumber(); | ||||||||
280 | break; | ||||||||
281 | case MachineOperand::MO_FrameIndex: | ||||||||
282 | case MachineOperand::MO_ConstantPoolIndex: | ||||||||
283 | case MachineOperand::MO_JumpTableIndex: | ||||||||
284 | OperandHash = Op.getIndex(); | ||||||||
285 | break; | ||||||||
286 | case MachineOperand::MO_GlobalAddress: | ||||||||
287 | case MachineOperand::MO_ExternalSymbol: | ||||||||
288 | // Global address / external symbol are too hard, don't bother, but do | ||||||||
289 | // pull in the offset. | ||||||||
290 | OperandHash = Op.getOffset(); | ||||||||
291 | break; | ||||||||
292 | default: | ||||||||
293 | break; | ||||||||
294 | } | ||||||||
295 | |||||||||
296 | Hash += ((OperandHash << 3) | Op.getType()) << (i & 31); | ||||||||
297 | } | ||||||||
298 | return Hash; | ||||||||
299 | } | ||||||||
300 | |||||||||
301 | /// HashEndOfMBB - Hash the last instruction in the MBB. | ||||||||
302 | static unsigned HashEndOfMBB(const MachineBasicBlock &MBB) { | ||||||||
303 | MachineBasicBlock::const_iterator I = MBB.getLastNonDebugInstr(); | ||||||||
304 | if (I == MBB.end()) | ||||||||
305 | return 0; | ||||||||
306 | |||||||||
307 | return HashMachineInstr(*I); | ||||||||
308 | } | ||||||||
309 | |||||||||
310 | /// Whether MI should be counted as an instruction when calculating common tail. | ||||||||
311 | static bool countsAsInstruction(const MachineInstr &MI) { | ||||||||
312 | return !(MI.isDebugInstr() || MI.isCFIInstruction()); | ||||||||
313 | } | ||||||||
314 | |||||||||
315 | /// Iterate backwards from the given iterator \p I, towards the beginning of the | ||||||||
316 | /// block. If a MI satisfying 'countsAsInstruction' is found, return an iterator | ||||||||
317 | /// pointing to that MI. If no such MI is found, return the end iterator. | ||||||||
318 | static MachineBasicBlock::iterator | ||||||||
319 | skipBackwardPastNonInstructions(MachineBasicBlock::iterator I, | ||||||||
320 | MachineBasicBlock *MBB) { | ||||||||
321 | while (I != MBB->begin()) { | ||||||||
322 | --I; | ||||||||
323 | if (countsAsInstruction(*I)) | ||||||||
324 | return I; | ||||||||
325 | } | ||||||||
326 | return MBB->end(); | ||||||||
327 | } | ||||||||
328 | |||||||||
329 | /// Given two machine basic blocks, return the number of instructions they | ||||||||
330 | /// actually have in common together at their end. If a common tail is found (at | ||||||||
331 | /// least by one instruction), then iterators for the first shared instruction | ||||||||
332 | /// in each block are returned as well. | ||||||||
333 | /// | ||||||||
334 | /// Non-instructions according to countsAsInstruction are ignored. | ||||||||
335 | static unsigned ComputeCommonTailLength(MachineBasicBlock *MBB1, | ||||||||
336 | MachineBasicBlock *MBB2, | ||||||||
337 | MachineBasicBlock::iterator &I1, | ||||||||
338 | MachineBasicBlock::iterator &I2) { | ||||||||
339 | MachineBasicBlock::iterator MBBI1 = MBB1->end(); | ||||||||
340 | MachineBasicBlock::iterator MBBI2 = MBB2->end(); | ||||||||
341 | |||||||||
342 | unsigned TailLen = 0; | ||||||||
343 | while (true) { | ||||||||
344 | MBBI1 = skipBackwardPastNonInstructions(MBBI1, MBB1); | ||||||||
345 | MBBI2 = skipBackwardPastNonInstructions(MBBI2, MBB2); | ||||||||
346 | if (MBBI1 == MBB1->end() || MBBI2 == MBB2->end()) | ||||||||
347 | break; | ||||||||
348 | if (!MBBI1->isIdenticalTo(*MBBI2) || | ||||||||
349 | // FIXME: This check is dubious. It's used to get around a problem where | ||||||||
350 | // people incorrectly expect inline asm directives to remain in the same | ||||||||
351 | // relative order. This is untenable because normal compiler | ||||||||
352 | // optimizations (like this one) may reorder and/or merge these | ||||||||
353 | // directives. | ||||||||
354 | MBBI1->isInlineAsm()) { | ||||||||
355 | break; | ||||||||
356 | } | ||||||||
357 | ++TailLen; | ||||||||
358 | I1 = MBBI1; | ||||||||
359 | I2 = MBBI2; | ||||||||
360 | } | ||||||||
361 | |||||||||
362 | return TailLen; | ||||||||
363 | } | ||||||||
364 | |||||||||
365 | void BranchFolder::replaceTailWithBranchTo(MachineBasicBlock::iterator OldInst, | ||||||||
366 | MachineBasicBlock &NewDest) { | ||||||||
367 | if (UpdateLiveIns) { | ||||||||
368 | // OldInst should always point to an instruction. | ||||||||
369 | MachineBasicBlock &OldMBB = *OldInst->getParent(); | ||||||||
370 | LiveRegs.clear(); | ||||||||
371 | LiveRegs.addLiveOuts(OldMBB); | ||||||||
372 | // Move backward to the place where will insert the jump. | ||||||||
373 | MachineBasicBlock::iterator I = OldMBB.end(); | ||||||||
374 | do { | ||||||||
375 | --I; | ||||||||
376 | LiveRegs.stepBackward(*I); | ||||||||
377 | } while (I != OldInst); | ||||||||
378 | |||||||||
379 | // Merging the tails may have switched some undef operand to non-undef ones. | ||||||||
380 | // Add IMPLICIT_DEFS into OldMBB as necessary to have a definition of the | ||||||||
381 | // register. | ||||||||
382 | for (MachineBasicBlock::RegisterMaskPair P : NewDest.liveins()) { | ||||||||
383 | // We computed the liveins with computeLiveIn earlier and should only see | ||||||||
384 | // full registers: | ||||||||
385 | assert(P.LaneMask == LaneBitmask::getAll() &&((P.LaneMask == LaneBitmask::getAll() && "Can only handle full register." ) ? static_cast<void> (0) : __assert_fail ("P.LaneMask == LaneBitmask::getAll() && \"Can only handle full register.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 386, __PRETTY_FUNCTION__)) | ||||||||
386 | "Can only handle full register.")((P.LaneMask == LaneBitmask::getAll() && "Can only handle full register." ) ? static_cast<void> (0) : __assert_fail ("P.LaneMask == LaneBitmask::getAll() && \"Can only handle full register.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 386, __PRETTY_FUNCTION__)); | ||||||||
387 | MCPhysReg Reg = P.PhysReg; | ||||||||
388 | if (!LiveRegs.available(*MRI, Reg)) | ||||||||
389 | continue; | ||||||||
390 | DebugLoc DL; | ||||||||
391 | BuildMI(OldMBB, OldInst, DL, TII->get(TargetOpcode::IMPLICIT_DEF), Reg); | ||||||||
392 | } | ||||||||
393 | } | ||||||||
394 | |||||||||
395 | TII->ReplaceTailWithBranchTo(OldInst, &NewDest); | ||||||||
396 | ++NumTailMerge; | ||||||||
397 | } | ||||||||
398 | |||||||||
399 | MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB, | ||||||||
400 | MachineBasicBlock::iterator BBI1, | ||||||||
401 | const BasicBlock *BB) { | ||||||||
402 | if (!TII->isLegalToSplitMBBAt(CurMBB, BBI1)) | ||||||||
403 | return nullptr; | ||||||||
404 | |||||||||
405 | MachineFunction &MF = *CurMBB.getParent(); | ||||||||
406 | |||||||||
407 | // Create the fall-through block. | ||||||||
408 | MachineFunction::iterator MBBI = CurMBB.getIterator(); | ||||||||
409 | MachineBasicBlock *NewMBB = MF.CreateMachineBasicBlock(BB); | ||||||||
410 | CurMBB.getParent()->insert(++MBBI, NewMBB); | ||||||||
411 | |||||||||
412 | // Move all the successors of this block to the specified block. | ||||||||
413 | NewMBB->transferSuccessors(&CurMBB); | ||||||||
414 | |||||||||
415 | // Add an edge from CurMBB to NewMBB for the fall-through. | ||||||||
416 | CurMBB.addSuccessor(NewMBB); | ||||||||
417 | |||||||||
418 | // Splice the code over. | ||||||||
419 | NewMBB->splice(NewMBB->end(), &CurMBB, BBI1, CurMBB.end()); | ||||||||
420 | |||||||||
421 | // NewMBB belongs to the same loop as CurMBB. | ||||||||
422 | if (MLI) | ||||||||
423 | if (MachineLoop *ML = MLI->getLoopFor(&CurMBB)) | ||||||||
424 | ML->addBasicBlockToLoop(NewMBB, MLI->getBase()); | ||||||||
425 | |||||||||
426 | // NewMBB inherits CurMBB's block frequency. | ||||||||
427 | MBBFreqInfo.setBlockFreq(NewMBB, MBBFreqInfo.getBlockFreq(&CurMBB)); | ||||||||
428 | |||||||||
429 | if (UpdateLiveIns) | ||||||||
430 | computeAndAddLiveIns(LiveRegs, *NewMBB); | ||||||||
431 | |||||||||
432 | // Add the new block to the EH scope. | ||||||||
433 | const auto &EHScopeI = EHScopeMembership.find(&CurMBB); | ||||||||
434 | if (EHScopeI != EHScopeMembership.end()) { | ||||||||
435 | auto n = EHScopeI->second; | ||||||||
436 | EHScopeMembership[NewMBB] = n; | ||||||||
437 | } | ||||||||
438 | |||||||||
439 | return NewMBB; | ||||||||
440 | } | ||||||||
441 | |||||||||
442 | /// EstimateRuntime - Make a rough estimate for how long it will take to run | ||||||||
443 | /// the specified code. | ||||||||
444 | static unsigned EstimateRuntime(MachineBasicBlock::iterator I, | ||||||||
445 | MachineBasicBlock::iterator E) { | ||||||||
446 | unsigned Time = 0; | ||||||||
447 | for (; I != E; ++I) { | ||||||||
448 | if (!countsAsInstruction(*I)) | ||||||||
449 | continue; | ||||||||
450 | if (I->isCall()) | ||||||||
451 | Time += 10; | ||||||||
452 | else if (I->mayLoadOrStore()) | ||||||||
453 | Time += 2; | ||||||||
454 | else | ||||||||
455 | ++Time; | ||||||||
456 | } | ||||||||
457 | return Time; | ||||||||
458 | } | ||||||||
459 | |||||||||
460 | // CurMBB needs to add an unconditional branch to SuccMBB (we removed these | ||||||||
461 | // branches temporarily for tail merging). In the case where CurMBB ends | ||||||||
462 | // with a conditional branch to the next block, optimize by reversing the | ||||||||
463 | // test and conditionally branching to SuccMBB instead. | ||||||||
464 | static void FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB, | ||||||||
465 | const TargetInstrInfo *TII) { | ||||||||
466 | MachineFunction *MF = CurMBB->getParent(); | ||||||||
467 | MachineFunction::iterator I = std::next(MachineFunction::iterator(CurMBB)); | ||||||||
468 | MachineBasicBlock *TBB = nullptr, *FBB = nullptr; | ||||||||
469 | SmallVector<MachineOperand, 4> Cond; | ||||||||
470 | DebugLoc dl = CurMBB->findBranchDebugLoc(); | ||||||||
471 | if (I != MF->end() && !TII->analyzeBranch(*CurMBB, TBB, FBB, Cond, true)) { | ||||||||
472 | MachineBasicBlock *NextBB = &*I; | ||||||||
473 | if (TBB == NextBB && !Cond.empty() && !FBB) { | ||||||||
474 | if (!TII->reverseBranchCondition(Cond)) { | ||||||||
475 | TII->removeBranch(*CurMBB); | ||||||||
476 | TII->insertBranch(*CurMBB, SuccBB, nullptr, Cond, dl); | ||||||||
477 | return; | ||||||||
478 | } | ||||||||
479 | } | ||||||||
480 | } | ||||||||
481 | TII->insertBranch(*CurMBB, SuccBB, nullptr, | ||||||||
482 | SmallVector<MachineOperand, 0>(), dl); | ||||||||
483 | } | ||||||||
484 | |||||||||
485 | bool | ||||||||
486 | BranchFolder::MergePotentialsElt::operator<(const MergePotentialsElt &o) const { | ||||||||
487 | if (getHash() < o.getHash()) | ||||||||
488 | return true; | ||||||||
489 | if (getHash() > o.getHash()) | ||||||||
490 | return false; | ||||||||
491 | if (getBlock()->getNumber() < o.getBlock()->getNumber()) | ||||||||
492 | return true; | ||||||||
493 | if (getBlock()->getNumber() > o.getBlock()->getNumber()) | ||||||||
494 | return false; | ||||||||
495 | // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing | ||||||||
496 | // an object with itself. | ||||||||
497 | #ifndef _GLIBCXX_DEBUG | ||||||||
498 | llvm_unreachable("Predecessor appears twice")::llvm::llvm_unreachable_internal("Predecessor appears twice" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 498); | ||||||||
499 | #else | ||||||||
500 | return false; | ||||||||
501 | #endif | ||||||||
502 | } | ||||||||
503 | |||||||||
504 | /// CountTerminators - Count the number of terminators in the given | ||||||||
505 | /// block and set I to the position of the first non-terminator, if there | ||||||||
506 | /// is one, or MBB->end() otherwise. | ||||||||
507 | static unsigned CountTerminators(MachineBasicBlock *MBB, | ||||||||
508 | MachineBasicBlock::iterator &I) { | ||||||||
509 | I = MBB->end(); | ||||||||
510 | unsigned NumTerms = 0; | ||||||||
511 | while (true) { | ||||||||
512 | if (I == MBB->begin()) { | ||||||||
513 | I = MBB->end(); | ||||||||
514 | break; | ||||||||
515 | } | ||||||||
516 | --I; | ||||||||
517 | if (!I->isTerminator()) break; | ||||||||
518 | ++NumTerms; | ||||||||
519 | } | ||||||||
520 | return NumTerms; | ||||||||
521 | } | ||||||||
522 | |||||||||
523 | /// A no successor, non-return block probably ends in unreachable and is cold. | ||||||||
524 | /// Also consider a block that ends in an indirect branch to be a return block, | ||||||||
525 | /// since many targets use plain indirect branches to return. | ||||||||
526 | static bool blockEndsInUnreachable(const MachineBasicBlock *MBB) { | ||||||||
527 | if (!MBB->succ_empty()) | ||||||||
528 | return false; | ||||||||
529 | if (MBB->empty()) | ||||||||
530 | return true; | ||||||||
531 | return !(MBB->back().isReturn() || MBB->back().isIndirectBranch()); | ||||||||
532 | } | ||||||||
533 | |||||||||
534 | /// ProfitableToMerge - Check if two machine basic blocks have a common tail | ||||||||
535 | /// and decide if it would be profitable to merge those tails. Return the | ||||||||
536 | /// length of the common tail and iterators to the first common instruction | ||||||||
537 | /// in each block. | ||||||||
538 | /// MBB1, MBB2 The blocks to check | ||||||||
539 | /// MinCommonTailLength Minimum size of tail block to be merged. | ||||||||
540 | /// CommonTailLen Out parameter to record the size of the shared tail between | ||||||||
541 | /// MBB1 and MBB2 | ||||||||
542 | /// I1, I2 Iterator references that will be changed to point to the first | ||||||||
543 | /// instruction in the common tail shared by MBB1,MBB2 | ||||||||
544 | /// SuccBB A common successor of MBB1, MBB2 which are in a canonical form | ||||||||
545 | /// relative to SuccBB | ||||||||
546 | /// PredBB The layout predecessor of SuccBB, if any. | ||||||||
547 | /// EHScopeMembership map from block to EH scope #. | ||||||||
548 | /// AfterPlacement True if we are merging blocks after layout. Stricter | ||||||||
549 | /// thresholds apply to prevent undoing tail-duplication. | ||||||||
550 | static bool | ||||||||
551 | ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2, | ||||||||
552 | unsigned MinCommonTailLength, unsigned &CommonTailLen, | ||||||||
553 | MachineBasicBlock::iterator &I1, | ||||||||
554 | MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB, | ||||||||
555 | MachineBasicBlock *PredBB, | ||||||||
556 | DenseMap<const MachineBasicBlock *, int> &EHScopeMembership, | ||||||||
557 | bool AfterPlacement, | ||||||||
558 | MBFIWrapper &MBBFreqInfo, | ||||||||
559 | ProfileSummaryInfo *PSI) { | ||||||||
560 | // It is never profitable to tail-merge blocks from two different EH scopes. | ||||||||
561 | if (!EHScopeMembership.empty()) { | ||||||||
562 | auto EHScope1 = EHScopeMembership.find(MBB1); | ||||||||
563 | assert(EHScope1 != EHScopeMembership.end())((EHScope1 != EHScopeMembership.end()) ? static_cast<void> (0) : __assert_fail ("EHScope1 != EHScopeMembership.end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 563, __PRETTY_FUNCTION__)); | ||||||||
564 | auto EHScope2 = EHScopeMembership.find(MBB2); | ||||||||
565 | assert(EHScope2 != EHScopeMembership.end())((EHScope2 != EHScopeMembership.end()) ? static_cast<void> (0) : __assert_fail ("EHScope2 != EHScopeMembership.end()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 565, __PRETTY_FUNCTION__)); | ||||||||
566 | if (EHScope1->second != EHScope2->second) | ||||||||
567 | return false; | ||||||||
568 | } | ||||||||
569 | |||||||||
570 | CommonTailLen = ComputeCommonTailLength(MBB1, MBB2, I1, I2); | ||||||||
571 | if (CommonTailLen == 0) | ||||||||
572 | return false; | ||||||||
573 | LLVM_DEBUG(dbgs() << "Common tail length of " << printMBBReference(*MBB1)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Common tail length of " << printMBBReference(*MBB1) << " and " << printMBBReference (*MBB2) << " is " << CommonTailLen << '\n'; } } while (false) | ||||||||
574 | << " and " << printMBBReference(*MBB2) << " is "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Common tail length of " << printMBBReference(*MBB1) << " and " << printMBBReference (*MBB2) << " is " << CommonTailLen << '\n'; } } while (false) | ||||||||
575 | << CommonTailLen << '\n')do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Common tail length of " << printMBBReference(*MBB1) << " and " << printMBBReference (*MBB2) << " is " << CommonTailLen << '\n'; } } while (false); | ||||||||
576 | |||||||||
577 | // Move the iterators to the beginning of the MBB if we only got debug | ||||||||
578 | // instructions before the tail. This is to avoid splitting a block when we | ||||||||
579 | // only got debug instructions before the tail (to be invariant on -g). | ||||||||
580 | if (skipDebugInstructionsForward(MBB1->begin(), MBB1->end()) == I1) | ||||||||
581 | I1 = MBB1->begin(); | ||||||||
582 | if (skipDebugInstructionsForward(MBB2->begin(), MBB2->end()) == I2) | ||||||||
583 | I2 = MBB2->begin(); | ||||||||
584 | |||||||||
585 | bool FullBlockTail1 = I1 == MBB1->begin(); | ||||||||
586 | bool FullBlockTail2 = I2 == MBB2->begin(); | ||||||||
587 | |||||||||
588 | // It's almost always profitable to merge any number of non-terminator | ||||||||
589 | // instructions with the block that falls through into the common successor. | ||||||||
590 | // This is true only for a single successor. For multiple successors, we are | ||||||||
591 | // trading a conditional branch for an unconditional one. | ||||||||
592 | // TODO: Re-visit successor size for non-layout tail merging. | ||||||||
593 | if ((MBB1 == PredBB || MBB2 == PredBB) && | ||||||||
594 | (!AfterPlacement || MBB1->succ_size() == 1)) { | ||||||||
595 | MachineBasicBlock::iterator I; | ||||||||
596 | unsigned NumTerms = CountTerminators(MBB1 == PredBB ? MBB2 : MBB1, I); | ||||||||
597 | if (CommonTailLen > NumTerms) | ||||||||
598 | return true; | ||||||||
599 | } | ||||||||
600 | |||||||||
601 | // If these are identical non-return blocks with no successors, merge them. | ||||||||
602 | // Such blocks are typically cold calls to noreturn functions like abort, and | ||||||||
603 | // are unlikely to become a fallthrough target after machine block placement. | ||||||||
604 | // Tail merging these blocks is unlikely to create additional unconditional | ||||||||
605 | // branches, and will reduce the size of this cold code. | ||||||||
606 | if (FullBlockTail1 && FullBlockTail2 && | ||||||||
607 | blockEndsInUnreachable(MBB1) && blockEndsInUnreachable(MBB2)) | ||||||||
608 | return true; | ||||||||
609 | |||||||||
610 | // If one of the blocks can be completely merged and happens to be in | ||||||||
611 | // a position where the other could fall through into it, merge any number | ||||||||
612 | // of instructions, because it can be done without a branch. | ||||||||
613 | // TODO: If the blocks are not adjacent, move one of them so that they are? | ||||||||
614 | if (MBB1->isLayoutSuccessor(MBB2) && FullBlockTail2) | ||||||||
615 | return true; | ||||||||
616 | if (MBB2->isLayoutSuccessor(MBB1) && FullBlockTail1) | ||||||||
617 | return true; | ||||||||
618 | |||||||||
619 | // If both blocks are identical and end in a branch, merge them unless they | ||||||||
620 | // both have a fallthrough predecessor and successor. | ||||||||
621 | // We can only do this after block placement because it depends on whether | ||||||||
622 | // there are fallthroughs, and we don't know until after layout. | ||||||||
623 | if (AfterPlacement && FullBlockTail1 && FullBlockTail2) { | ||||||||
624 | auto BothFallThrough = [](MachineBasicBlock *MBB) { | ||||||||
625 | if (MBB->succ_size() != 0 && !MBB->canFallThrough()) | ||||||||
626 | return false; | ||||||||
627 | MachineFunction::iterator I(MBB); | ||||||||
628 | MachineFunction *MF = MBB->getParent(); | ||||||||
629 | return (MBB != &*MF->begin()) && std::prev(I)->canFallThrough(); | ||||||||
630 | }; | ||||||||
631 | if (!BothFallThrough(MBB1) || !BothFallThrough(MBB2)) | ||||||||
632 | return true; | ||||||||
633 | } | ||||||||
634 | |||||||||
635 | // If both blocks have an unconditional branch temporarily stripped out, | ||||||||
636 | // count that as an additional common instruction for the following | ||||||||
637 | // heuristics. This heuristic is only accurate for single-succ blocks, so to | ||||||||
638 | // make sure that during layout merging and duplicating don't crash, we check | ||||||||
639 | // for that when merging during layout. | ||||||||
640 | unsigned EffectiveTailLen = CommonTailLen; | ||||||||
641 | if (SuccBB && MBB1 != PredBB && MBB2 != PredBB && | ||||||||
642 | (MBB1->succ_size() == 1 || !AfterPlacement) && | ||||||||
643 | !MBB1->back().isBarrier() && | ||||||||
644 | !MBB2->back().isBarrier()) | ||||||||
645 | ++EffectiveTailLen; | ||||||||
646 | |||||||||
647 | // Check if the common tail is long enough to be worthwhile. | ||||||||
648 | if (EffectiveTailLen >= MinCommonTailLength) | ||||||||
649 | return true; | ||||||||
650 | |||||||||
651 | // If we are optimizing for code size, 2 instructions in common is enough if | ||||||||
652 | // we don't have to split a block. At worst we will be introducing 1 new | ||||||||
653 | // branch instruction, which is likely to be smaller than the 2 | ||||||||
654 | // instructions that would be deleted in the merge. | ||||||||
655 | MachineFunction *MF = MBB1->getParent(); | ||||||||
656 | bool OptForSize = | ||||||||
657 | MF->getFunction().hasOptSize() || | ||||||||
658 | (llvm::shouldOptimizeForSize(MBB1, PSI, &MBBFreqInfo) && | ||||||||
659 | llvm::shouldOptimizeForSize(MBB2, PSI, &MBBFreqInfo)); | ||||||||
660 | return EffectiveTailLen >= 2 && OptForSize && | ||||||||
661 | (FullBlockTail1 || FullBlockTail2); | ||||||||
662 | } | ||||||||
663 | |||||||||
664 | unsigned BranchFolder::ComputeSameTails(unsigned CurHash, | ||||||||
665 | unsigned MinCommonTailLength, | ||||||||
666 | MachineBasicBlock *SuccBB, | ||||||||
667 | MachineBasicBlock *PredBB) { | ||||||||
668 | unsigned maxCommonTailLength = 0U; | ||||||||
669 | SameTails.clear(); | ||||||||
670 | MachineBasicBlock::iterator TrialBBI1, TrialBBI2; | ||||||||
671 | MPIterator HighestMPIter = std::prev(MergePotentials.end()); | ||||||||
672 | for (MPIterator CurMPIter = std::prev(MergePotentials.end()), | ||||||||
673 | B = MergePotentials.begin(); | ||||||||
674 | CurMPIter != B && CurMPIter->getHash() == CurHash; --CurMPIter) { | ||||||||
675 | for (MPIterator I = std::prev(CurMPIter); I->getHash() == CurHash; --I) { | ||||||||
676 | unsigned CommonTailLen; | ||||||||
677 | if (ProfitableToMerge(CurMPIter->getBlock(), I->getBlock(), | ||||||||
678 | MinCommonTailLength, | ||||||||
679 | CommonTailLen, TrialBBI1, TrialBBI2, | ||||||||
680 | SuccBB, PredBB, | ||||||||
681 | EHScopeMembership, | ||||||||
682 | AfterBlockPlacement, MBBFreqInfo, PSI)) { | ||||||||
683 | if (CommonTailLen > maxCommonTailLength) { | ||||||||
684 | SameTails.clear(); | ||||||||
685 | maxCommonTailLength = CommonTailLen; | ||||||||
686 | HighestMPIter = CurMPIter; | ||||||||
687 | SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1)); | ||||||||
688 | } | ||||||||
689 | if (HighestMPIter == CurMPIter && | ||||||||
690 | CommonTailLen == maxCommonTailLength) | ||||||||
691 | SameTails.push_back(SameTailElt(I, TrialBBI2)); | ||||||||
692 | } | ||||||||
693 | if (I == B) | ||||||||
694 | break; | ||||||||
695 | } | ||||||||
696 | } | ||||||||
697 | return maxCommonTailLength; | ||||||||
698 | } | ||||||||
699 | |||||||||
700 | void BranchFolder::RemoveBlocksWithHash(unsigned CurHash, | ||||||||
701 | MachineBasicBlock *SuccBB, | ||||||||
702 | MachineBasicBlock *PredBB) { | ||||||||
703 | MPIterator CurMPIter, B; | ||||||||
704 | for (CurMPIter = std::prev(MergePotentials.end()), | ||||||||
705 | B = MergePotentials.begin(); | ||||||||
706 | CurMPIter->getHash() == CurHash; --CurMPIter) { | ||||||||
707 | // Put the unconditional branch back, if we need one. | ||||||||
708 | MachineBasicBlock *CurMBB = CurMPIter->getBlock(); | ||||||||
709 | if (SuccBB && CurMBB != PredBB) | ||||||||
710 | FixTail(CurMBB, SuccBB, TII); | ||||||||
711 | if (CurMPIter == B) | ||||||||
712 | break; | ||||||||
713 | } | ||||||||
714 | if (CurMPIter->getHash() != CurHash) | ||||||||
715 | CurMPIter++; | ||||||||
716 | MergePotentials.erase(CurMPIter, MergePotentials.end()); | ||||||||
717 | } | ||||||||
718 | |||||||||
719 | bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB, | ||||||||
720 | MachineBasicBlock *SuccBB, | ||||||||
721 | unsigned maxCommonTailLength, | ||||||||
722 | unsigned &commonTailIndex) { | ||||||||
723 | commonTailIndex = 0; | ||||||||
724 | unsigned TimeEstimate = ~0U; | ||||||||
725 | for (unsigned i = 0, e = SameTails.size(); i != e; ++i) { | ||||||||
726 | // Use PredBB if possible; that doesn't require a new branch. | ||||||||
727 | if (SameTails[i].getBlock() == PredBB) { | ||||||||
728 | commonTailIndex = i; | ||||||||
729 | break; | ||||||||
730 | } | ||||||||
731 | // Otherwise, make a (fairly bogus) choice based on estimate of | ||||||||
732 | // how long it will take the various blocks to execute. | ||||||||
733 | unsigned t = EstimateRuntime(SameTails[i].getBlock()->begin(), | ||||||||
734 | SameTails[i].getTailStartPos()); | ||||||||
735 | if (t <= TimeEstimate) { | ||||||||
736 | TimeEstimate = t; | ||||||||
737 | commonTailIndex = i; | ||||||||
738 | } | ||||||||
739 | } | ||||||||
740 | |||||||||
741 | MachineBasicBlock::iterator BBI = | ||||||||
742 | SameTails[commonTailIndex].getTailStartPos(); | ||||||||
743 | MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock(); | ||||||||
744 | |||||||||
745 | LLVM_DEBUG(dbgs() << "\nSplitting " << printMBBReference(*MBB) << ", size "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nSplitting " << printMBBReference (*MBB) << ", size " << maxCommonTailLength; } } while (false) | ||||||||
746 | << maxCommonTailLength)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nSplitting " << printMBBReference (*MBB) << ", size " << maxCommonTailLength; } } while (false); | ||||||||
747 | |||||||||
748 | // If the split block unconditionally falls-thru to SuccBB, it will be | ||||||||
749 | // merged. In control flow terms it should then take SuccBB's name. e.g. If | ||||||||
750 | // SuccBB is an inner loop, the common tail is still part of the inner loop. | ||||||||
751 | const BasicBlock *BB = (SuccBB && MBB->succ_size() == 1) ? | ||||||||
752 | SuccBB->getBasicBlock() : MBB->getBasicBlock(); | ||||||||
753 | MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI, BB); | ||||||||
754 | if (!newMBB) { | ||||||||
755 | LLVM_DEBUG(dbgs() << "... failed!")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "... failed!"; } } while (false); | ||||||||
756 | return false; | ||||||||
757 | } | ||||||||
758 | |||||||||
759 | SameTails[commonTailIndex].setBlock(newMBB); | ||||||||
760 | SameTails[commonTailIndex].setTailStartPos(newMBB->begin()); | ||||||||
761 | |||||||||
762 | // If we split PredBB, newMBB is the new predecessor. | ||||||||
763 | if (PredBB == MBB) | ||||||||
764 | PredBB = newMBB; | ||||||||
765 | |||||||||
766 | return true; | ||||||||
767 | } | ||||||||
768 | |||||||||
769 | static void | ||||||||
770 | mergeOperations(MachineBasicBlock::iterator MBBIStartPos, | ||||||||
771 | MachineBasicBlock &MBBCommon) { | ||||||||
772 | MachineBasicBlock *MBB = MBBIStartPos->getParent(); | ||||||||
773 | // Note CommonTailLen does not necessarily matches the size of | ||||||||
774 | // the common BB nor all its instructions because of debug | ||||||||
775 | // instructions differences. | ||||||||
776 | unsigned CommonTailLen = 0; | ||||||||
777 | for (auto E = MBB->end(); MBBIStartPos != E; ++MBBIStartPos) | ||||||||
778 | ++CommonTailLen; | ||||||||
779 | |||||||||
780 | MachineBasicBlock::reverse_iterator MBBI = MBB->rbegin(); | ||||||||
781 | MachineBasicBlock::reverse_iterator MBBIE = MBB->rend(); | ||||||||
782 | MachineBasicBlock::reverse_iterator MBBICommon = MBBCommon.rbegin(); | ||||||||
783 | MachineBasicBlock::reverse_iterator MBBIECommon = MBBCommon.rend(); | ||||||||
784 | |||||||||
785 | while (CommonTailLen--) { | ||||||||
786 | assert(MBBI != MBBIE && "Reached BB end within common tail length!")((MBBI != MBBIE && "Reached BB end within common tail length!" ) ? static_cast<void> (0) : __assert_fail ("MBBI != MBBIE && \"Reached BB end within common tail length!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 786, __PRETTY_FUNCTION__)); | ||||||||
787 | (void)MBBIE; | ||||||||
788 | |||||||||
789 | if (!countsAsInstruction(*MBBI)) { | ||||||||
790 | ++MBBI; | ||||||||
791 | continue; | ||||||||
792 | } | ||||||||
793 | |||||||||
794 | while ((MBBICommon != MBBIECommon) && !countsAsInstruction(*MBBICommon)) | ||||||||
795 | ++MBBICommon; | ||||||||
796 | |||||||||
797 | assert(MBBICommon != MBBIECommon &&((MBBICommon != MBBIECommon && "Reached BB end within common tail length!" ) ? static_cast<void> (0) : __assert_fail ("MBBICommon != MBBIECommon && \"Reached BB end within common tail length!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 798, __PRETTY_FUNCTION__)) | ||||||||
798 | "Reached BB end within common tail length!")((MBBICommon != MBBIECommon && "Reached BB end within common tail length!" ) ? static_cast<void> (0) : __assert_fail ("MBBICommon != MBBIECommon && \"Reached BB end within common tail length!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 798, __PRETTY_FUNCTION__)); | ||||||||
799 | assert(MBBICommon->isIdenticalTo(*MBBI) && "Expected matching MIIs!")((MBBICommon->isIdenticalTo(*MBBI) && "Expected matching MIIs!" ) ? static_cast<void> (0) : __assert_fail ("MBBICommon->isIdenticalTo(*MBBI) && \"Expected matching MIIs!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 799, __PRETTY_FUNCTION__)); | ||||||||
800 | |||||||||
801 | // Merge MMOs from memory operations in the common block. | ||||||||
802 | if (MBBICommon->mayLoadOrStore()) | ||||||||
803 | MBBICommon->cloneMergedMemRefs(*MBB->getParent(), {&*MBBICommon, &*MBBI}); | ||||||||
804 | // Drop undef flags if they aren't present in all merged instructions. | ||||||||
805 | for (unsigned I = 0, E = MBBICommon->getNumOperands(); I != E; ++I) { | ||||||||
806 | MachineOperand &MO = MBBICommon->getOperand(I); | ||||||||
807 | if (MO.isReg() && MO.isUndef()) { | ||||||||
808 | const MachineOperand &OtherMO = MBBI->getOperand(I); | ||||||||
809 | if (!OtherMO.isUndef()) | ||||||||
810 | MO.setIsUndef(false); | ||||||||
811 | } | ||||||||
812 | } | ||||||||
813 | |||||||||
814 | ++MBBI; | ||||||||
815 | ++MBBICommon; | ||||||||
816 | } | ||||||||
817 | } | ||||||||
818 | |||||||||
819 | void BranchFolder::mergeCommonTails(unsigned commonTailIndex) { | ||||||||
820 | MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock(); | ||||||||
821 | |||||||||
822 | std::vector<MachineBasicBlock::iterator> NextCommonInsts(SameTails.size()); | ||||||||
823 | for (unsigned int i = 0 ; i != SameTails.size() ; ++i) { | ||||||||
824 | if (i != commonTailIndex) { | ||||||||
825 | NextCommonInsts[i] = SameTails[i].getTailStartPos(); | ||||||||
826 | mergeOperations(SameTails[i].getTailStartPos(), *MBB); | ||||||||
827 | } else { | ||||||||
828 | assert(SameTails[i].getTailStartPos() == MBB->begin() &&((SameTails[i].getTailStartPos() == MBB->begin() && "MBB is not a common tail only block") ? static_cast<void > (0) : __assert_fail ("SameTails[i].getTailStartPos() == MBB->begin() && \"MBB is not a common tail only block\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 829, __PRETTY_FUNCTION__)) | ||||||||
829 | "MBB is not a common tail only block")((SameTails[i].getTailStartPos() == MBB->begin() && "MBB is not a common tail only block") ? static_cast<void > (0) : __assert_fail ("SameTails[i].getTailStartPos() == MBB->begin() && \"MBB is not a common tail only block\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 829, __PRETTY_FUNCTION__)); | ||||||||
830 | } | ||||||||
831 | } | ||||||||
832 | |||||||||
833 | for (auto &MI : *MBB) { | ||||||||
834 | if (!countsAsInstruction(MI)) | ||||||||
835 | continue; | ||||||||
836 | DebugLoc DL = MI.getDebugLoc(); | ||||||||
837 | for (unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) { | ||||||||
838 | if (i == commonTailIndex) | ||||||||
839 | continue; | ||||||||
840 | |||||||||
841 | auto &Pos = NextCommonInsts[i]; | ||||||||
842 | assert(Pos != SameTails[i].getBlock()->end() &&((Pos != SameTails[i].getBlock()->end() && "Reached BB end within common tail" ) ? static_cast<void> (0) : __assert_fail ("Pos != SameTails[i].getBlock()->end() && \"Reached BB end within common tail\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 843, __PRETTY_FUNCTION__)) | ||||||||
843 | "Reached BB end within common tail")((Pos != SameTails[i].getBlock()->end() && "Reached BB end within common tail" ) ? static_cast<void> (0) : __assert_fail ("Pos != SameTails[i].getBlock()->end() && \"Reached BB end within common tail\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 843, __PRETTY_FUNCTION__)); | ||||||||
844 | while (!countsAsInstruction(*Pos)) { | ||||||||
845 | ++Pos; | ||||||||
846 | assert(Pos != SameTails[i].getBlock()->end() &&((Pos != SameTails[i].getBlock()->end() && "Reached BB end within common tail" ) ? static_cast<void> (0) : __assert_fail ("Pos != SameTails[i].getBlock()->end() && \"Reached BB end within common tail\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 847, __PRETTY_FUNCTION__)) | ||||||||
847 | "Reached BB end within common tail")((Pos != SameTails[i].getBlock()->end() && "Reached BB end within common tail" ) ? static_cast<void> (0) : __assert_fail ("Pos != SameTails[i].getBlock()->end() && \"Reached BB end within common tail\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 847, __PRETTY_FUNCTION__)); | ||||||||
848 | } | ||||||||
849 | assert(MI.isIdenticalTo(*Pos) && "Expected matching MIIs!")((MI.isIdenticalTo(*Pos) && "Expected matching MIIs!" ) ? static_cast<void> (0) : __assert_fail ("MI.isIdenticalTo(*Pos) && \"Expected matching MIIs!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 849, __PRETTY_FUNCTION__)); | ||||||||
850 | DL = DILocation::getMergedLocation(DL, Pos->getDebugLoc()); | ||||||||
851 | NextCommonInsts[i] = ++Pos; | ||||||||
852 | } | ||||||||
853 | MI.setDebugLoc(DL); | ||||||||
854 | } | ||||||||
855 | |||||||||
856 | if (UpdateLiveIns) { | ||||||||
857 | LivePhysRegs NewLiveIns(*TRI); | ||||||||
858 | computeLiveIns(NewLiveIns, *MBB); | ||||||||
859 | LiveRegs.init(*TRI); | ||||||||
860 | |||||||||
861 | // The flag merging may lead to some register uses no longer using the | ||||||||
862 | // <undef> flag, add IMPLICIT_DEFs in the predecessors as necessary. | ||||||||
863 | for (MachineBasicBlock *Pred : MBB->predecessors()) { | ||||||||
864 | LiveRegs.clear(); | ||||||||
865 | LiveRegs.addLiveOuts(*Pred); | ||||||||
866 | MachineBasicBlock::iterator InsertBefore = Pred->getFirstTerminator(); | ||||||||
867 | for (unsigned Reg : NewLiveIns) { | ||||||||
868 | if (!LiveRegs.available(*MRI, Reg)) | ||||||||
869 | continue; | ||||||||
870 | DebugLoc DL; | ||||||||
871 | BuildMI(*Pred, InsertBefore, DL, TII->get(TargetOpcode::IMPLICIT_DEF), | ||||||||
872 | Reg); | ||||||||
873 | } | ||||||||
874 | } | ||||||||
875 | |||||||||
876 | MBB->clearLiveIns(); | ||||||||
877 | addLiveIns(*MBB, NewLiveIns); | ||||||||
878 | } | ||||||||
879 | } | ||||||||
880 | |||||||||
881 | // See if any of the blocks in MergePotentials (which all have SuccBB as a | ||||||||
882 | // successor, or all have no successor if it is null) can be tail-merged. | ||||||||
883 | // If there is a successor, any blocks in MergePotentials that are not | ||||||||
884 | // tail-merged and are not immediately before Succ must have an unconditional | ||||||||
885 | // branch to Succ added (but the predecessor/successor lists need no | ||||||||
886 | // adjustment). The lone predecessor of Succ that falls through into Succ, | ||||||||
887 | // if any, is given in PredBB. | ||||||||
888 | // MinCommonTailLength - Except for the special cases below, tail-merge if | ||||||||
889 | // there are at least this many instructions in common. | ||||||||
890 | bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB, | ||||||||
891 | MachineBasicBlock *PredBB, | ||||||||
892 | unsigned MinCommonTailLength) { | ||||||||
893 | bool MadeChange = false; | ||||||||
894 | |||||||||
895 | LLVM_DEBUG(do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
896 | dbgs() << "\nTryTailMergeBlocks: ";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
897 | for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i) dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
898 | << printMBBReference(*MergePotentials[i].getBlock())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
899 | << (i == e - 1 ? "" : ", ");do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
900 | dbgs() << "\n"; if (SuccBB) {do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
901 | dbgs() << " with successor " << printMBBReference(*SuccBB) << '\n';do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
902 | if (PredBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
903 | dbgs() << " which has fall-through from "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
904 | << printMBBReference(*PredBB) << "\n";do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
905 | } dbgs() << "Looking for common tails of at least "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
906 | << MinCommonTailLength << " instruction"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false) | ||||||||
907 | << (MinCommonTailLength == 1 ? "" : "s") << '\n';)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nTryTailMergeBlocks: " ; for (unsigned i = 0, e = MergePotentials.size(); i != e; ++ i) dbgs() << printMBBReference(*MergePotentials[i].getBlock ()) << (i == e - 1 ? "" : ", "); dbgs() << "\n"; if (SuccBB) { dbgs() << " with successor " << printMBBReference (*SuccBB) << '\n'; if (PredBB) dbgs() << " which has fall-through from " << printMBBReference(*PredBB) << "\n"; } dbgs() << "Looking for common tails of at least " << MinCommonTailLength << " instruction" << (MinCommonTailLength == 1 ? "" : "s") << '\n';; } } while (false); | ||||||||
908 | |||||||||
909 | // Sort by hash value so that blocks with identical end sequences sort | ||||||||
910 | // together. | ||||||||
911 | array_pod_sort(MergePotentials.begin(), MergePotentials.end()); | ||||||||
912 | |||||||||
913 | // Walk through equivalence sets looking for actual exact matches. | ||||||||
914 | while (MergePotentials.size() > 1) { | ||||||||
915 | unsigned CurHash = MergePotentials.back().getHash(); | ||||||||
916 | |||||||||
917 | // Build SameTails, identifying the set of blocks with this hash code | ||||||||
918 | // and with the maximum number of instructions in common. | ||||||||
919 | unsigned maxCommonTailLength = ComputeSameTails(CurHash, | ||||||||
920 | MinCommonTailLength, | ||||||||
921 | SuccBB, PredBB); | ||||||||
922 | |||||||||
923 | // If we didn't find any pair that has at least MinCommonTailLength | ||||||||
924 | // instructions in common, remove all blocks with this hash code and retry. | ||||||||
925 | if (SameTails.empty()) { | ||||||||
926 | RemoveBlocksWithHash(CurHash, SuccBB, PredBB); | ||||||||
927 | continue; | ||||||||
928 | } | ||||||||
929 | |||||||||
930 | // If one of the blocks is the entire common tail (and not the entry | ||||||||
931 | // block, which we can't jump to), we can treat all blocks with this same | ||||||||
932 | // tail at once. Use PredBB if that is one of the possibilities, as that | ||||||||
933 | // will not introduce any extra branches. | ||||||||
934 | MachineBasicBlock *EntryBB = | ||||||||
935 | &MergePotentials.front().getBlock()->getParent()->front(); | ||||||||
936 | unsigned commonTailIndex = SameTails.size(); | ||||||||
937 | // If there are two blocks, check to see if one can be made to fall through | ||||||||
938 | // into the other. | ||||||||
939 | if (SameTails.size() == 2 && | ||||||||
940 | SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) && | ||||||||
941 | SameTails[1].tailIsWholeBlock()) | ||||||||
942 | commonTailIndex = 1; | ||||||||
943 | else if (SameTails.size() == 2 && | ||||||||
944 | SameTails[1].getBlock()->isLayoutSuccessor( | ||||||||
945 | SameTails[0].getBlock()) && | ||||||||
946 | SameTails[0].tailIsWholeBlock()) | ||||||||
947 | commonTailIndex = 0; | ||||||||
948 | else { | ||||||||
949 | // Otherwise just pick one, favoring the fall-through predecessor if | ||||||||
950 | // there is one. | ||||||||
951 | for (unsigned i = 0, e = SameTails.size(); i != e; ++i) { | ||||||||
952 | MachineBasicBlock *MBB = SameTails[i].getBlock(); | ||||||||
953 | if (MBB == EntryBB && SameTails[i].tailIsWholeBlock()) | ||||||||
954 | continue; | ||||||||
955 | if (MBB == PredBB) { | ||||||||
956 | commonTailIndex = i; | ||||||||
957 | break; | ||||||||
958 | } | ||||||||
959 | if (SameTails[i].tailIsWholeBlock()) | ||||||||
960 | commonTailIndex = i; | ||||||||
961 | } | ||||||||
962 | } | ||||||||
963 | |||||||||
964 | if (commonTailIndex == SameTails.size() || | ||||||||
965 | (SameTails[commonTailIndex].getBlock() == PredBB && | ||||||||
966 | !SameTails[commonTailIndex].tailIsWholeBlock())) { | ||||||||
967 | // None of the blocks consist entirely of the common tail. | ||||||||
968 | // Split a block so that one does. | ||||||||
969 | if (!CreateCommonTailOnlyBlock(PredBB, SuccBB, | ||||||||
970 | maxCommonTailLength, commonTailIndex)) { | ||||||||
971 | RemoveBlocksWithHash(CurHash, SuccBB, PredBB); | ||||||||
972 | continue; | ||||||||
973 | } | ||||||||
974 | } | ||||||||
975 | |||||||||
976 | MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock(); | ||||||||
977 | |||||||||
978 | // Recompute common tail MBB's edge weights and block frequency. | ||||||||
979 | setCommonTailEdgeWeights(*MBB); | ||||||||
980 | |||||||||
981 | // Merge debug locations, MMOs and undef flags across identical instructions | ||||||||
982 | // for common tail. | ||||||||
983 | mergeCommonTails(commonTailIndex); | ||||||||
984 | |||||||||
985 | // MBB is common tail. Adjust all other BB's to jump to this one. | ||||||||
986 | // Traversal must be forwards so erases work. | ||||||||
987 | LLVM_DEBUG(dbgs() << "\nUsing common tail in " << printMBBReference(*MBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nUsing common tail in " << printMBBReference(*MBB) << " for "; } } while (false) | ||||||||
988 | << " for ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nUsing common tail in " << printMBBReference(*MBB) << " for "; } } while (false); | ||||||||
989 | for (unsigned int i=0, e = SameTails.size(); i != e; ++i) { | ||||||||
990 | if (commonTailIndex == i) | ||||||||
991 | continue; | ||||||||
992 | LLVM_DEBUG(dbgs() << printMBBReference(*SameTails[i].getBlock())do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << printMBBReference(*SameTails [i].getBlock()) << (i == e - 1 ? "" : ", "); } } while ( false) | ||||||||
993 | << (i == e - 1 ? "" : ", "))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << printMBBReference(*SameTails [i].getBlock()) << (i == e - 1 ? "" : ", "); } } while ( false); | ||||||||
994 | // Hack the end off BB i, making it jump to BB commonTailIndex instead. | ||||||||
995 | replaceTailWithBranchTo(SameTails[i].getTailStartPos(), *MBB); | ||||||||
996 | // BB i is no longer a predecessor of SuccBB; remove it from the worklist. | ||||||||
997 | MergePotentials.erase(SameTails[i].getMPIter()); | ||||||||
998 | } | ||||||||
999 | LLVM_DEBUG(dbgs() << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\n"; } } while (false); | ||||||||
1000 | // We leave commonTailIndex in the worklist in case there are other blocks | ||||||||
1001 | // that match it with a smaller number of instructions. | ||||||||
1002 | MadeChange = true; | ||||||||
1003 | } | ||||||||
1004 | return MadeChange; | ||||||||
1005 | } | ||||||||
1006 | |||||||||
1007 | bool BranchFolder::TailMergeBlocks(MachineFunction &MF) { | ||||||||
1008 | bool MadeChange = false; | ||||||||
1009 | if (!EnableTailMerge) | ||||||||
1010 | return MadeChange; | ||||||||
1011 | |||||||||
1012 | // First find blocks with no successors. | ||||||||
1013 | // Block placement may create new tail merging opportunities for these blocks. | ||||||||
1014 | MergePotentials.clear(); | ||||||||
1015 | for (MachineBasicBlock &MBB : MF) { | ||||||||
1016 | if (MergePotentials.size() == TailMergeThreshold) | ||||||||
1017 | break; | ||||||||
1018 | if (!TriedMerging.count(&MBB) && MBB.succ_empty()) | ||||||||
1019 | MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(MBB), &MBB)); | ||||||||
1020 | } | ||||||||
1021 | |||||||||
1022 | // If this is a large problem, avoid visiting the same basic blocks | ||||||||
1023 | // multiple times. | ||||||||
1024 | if (MergePotentials.size() == TailMergeThreshold) | ||||||||
1025 | for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i) | ||||||||
1026 | TriedMerging.insert(MergePotentials[i].getBlock()); | ||||||||
1027 | |||||||||
1028 | // See if we can do any tail merging on those. | ||||||||
1029 | if (MergePotentials.size() >= 2) | ||||||||
1030 | MadeChange |= TryTailMergeBlocks(nullptr, nullptr, MinCommonTailLength); | ||||||||
1031 | |||||||||
1032 | // Look at blocks (IBB) with multiple predecessors (PBB). | ||||||||
1033 | // We change each predecessor to a canonical form, by | ||||||||
1034 | // (1) temporarily removing any unconditional branch from the predecessor | ||||||||
1035 | // to IBB, and | ||||||||
1036 | // (2) alter conditional branches so they branch to the other block | ||||||||
1037 | // not IBB; this may require adding back an unconditional branch to IBB | ||||||||
1038 | // later, where there wasn't one coming in. E.g. | ||||||||
1039 | // Bcc IBB | ||||||||
1040 | // fallthrough to QBB | ||||||||
1041 | // here becomes | ||||||||
1042 | // Bncc QBB | ||||||||
1043 | // with a conceptual B to IBB after that, which never actually exists. | ||||||||
1044 | // With those changes, we see whether the predecessors' tails match, | ||||||||
1045 | // and merge them if so. We change things out of canonical form and | ||||||||
1046 | // back to the way they were later in the process. (OptimizeBranches | ||||||||
1047 | // would undo some of this, but we can't use it, because we'd get into | ||||||||
1048 | // a compile-time infinite loop repeatedly doing and undoing the same | ||||||||
1049 | // transformations.) | ||||||||
1050 | |||||||||
1051 | for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end(); | ||||||||
1052 | I != E; ++I) { | ||||||||
1053 | if (I->pred_size() < 2) continue; | ||||||||
1054 | SmallPtrSet<MachineBasicBlock *, 8> UniquePreds; | ||||||||
1055 | MachineBasicBlock *IBB = &*I; | ||||||||
1056 | MachineBasicBlock *PredBB = &*std::prev(I); | ||||||||
1057 | MergePotentials.clear(); | ||||||||
1058 | MachineLoop *ML; | ||||||||
1059 | |||||||||
1060 | // Bail if merging after placement and IBB is the loop header because | ||||||||
1061 | // -- If merging predecessors that belong to the same loop as IBB, the | ||||||||
1062 | // common tail of merged predecessors may become the loop top if block | ||||||||
1063 | // placement is called again and the predecessors may branch to this common | ||||||||
1064 | // tail and require more branches. This can be relaxed if | ||||||||
1065 | // MachineBlockPlacement::findBestLoopTop is more flexible. | ||||||||
1066 | // --If merging predecessors that do not belong to the same loop as IBB, the | ||||||||
1067 | // loop info of IBB's loop and the other loops may be affected. Calling the | ||||||||
1068 | // block placement again may make big change to the layout and eliminate the | ||||||||
1069 | // reason to do tail merging here. | ||||||||
1070 | if (AfterBlockPlacement && MLI) { | ||||||||
1071 | ML = MLI->getLoopFor(IBB); | ||||||||
1072 | if (ML && IBB == ML->getHeader()) | ||||||||
1073 | continue; | ||||||||
1074 | } | ||||||||
1075 | |||||||||
1076 | for (MachineBasicBlock *PBB : I->predecessors()) { | ||||||||
1077 | if (MergePotentials.size() == TailMergeThreshold) | ||||||||
1078 | break; | ||||||||
1079 | |||||||||
1080 | if (TriedMerging.count(PBB)) | ||||||||
1081 | continue; | ||||||||
1082 | |||||||||
1083 | // Skip blocks that loop to themselves, can't tail merge these. | ||||||||
1084 | if (PBB == IBB) | ||||||||
1085 | continue; | ||||||||
1086 | |||||||||
1087 | // Visit each predecessor only once. | ||||||||
1088 | if (!UniquePreds.insert(PBB).second) | ||||||||
1089 | continue; | ||||||||
1090 | |||||||||
1091 | // Skip blocks which may jump to a landing pad. Can't tail merge these. | ||||||||
1092 | if (PBB->hasEHPadSuccessor()) | ||||||||
1093 | continue; | ||||||||
1094 | |||||||||
1095 | // After block placement, only consider predecessors that belong to the | ||||||||
1096 | // same loop as IBB. The reason is the same as above when skipping loop | ||||||||
1097 | // header. | ||||||||
1098 | if (AfterBlockPlacement && MLI) | ||||||||
1099 | if (ML != MLI->getLoopFor(PBB)) | ||||||||
1100 | continue; | ||||||||
1101 | |||||||||
1102 | MachineBasicBlock *TBB = nullptr, *FBB = nullptr; | ||||||||
1103 | SmallVector<MachineOperand, 4> Cond; | ||||||||
1104 | if (!TII->analyzeBranch(*PBB, TBB, FBB, Cond, true)) { | ||||||||
1105 | // Failing case: IBB is the target of a cbr, and we cannot reverse the | ||||||||
1106 | // branch. | ||||||||
1107 | SmallVector<MachineOperand, 4> NewCond(Cond); | ||||||||
1108 | if (!Cond.empty() && TBB == IBB) { | ||||||||
1109 | if (TII->reverseBranchCondition(NewCond)) | ||||||||
1110 | continue; | ||||||||
1111 | // This is the QBB case described above | ||||||||
1112 | if (!FBB) { | ||||||||
1113 | auto Next = ++PBB->getIterator(); | ||||||||
1114 | if (Next != MF.end()) | ||||||||
1115 | FBB = &*Next; | ||||||||
1116 | } | ||||||||
1117 | } | ||||||||
1118 | |||||||||
1119 | // Remove the unconditional branch at the end, if any. | ||||||||
1120 | if (TBB && (Cond.empty() || FBB)) { | ||||||||
1121 | DebugLoc dl = PBB->findBranchDebugLoc(); | ||||||||
1122 | TII->removeBranch(*PBB); | ||||||||
1123 | if (!Cond.empty()) | ||||||||
1124 | // reinsert conditional branch only, for now | ||||||||
1125 | TII->insertBranch(*PBB, (TBB == IBB) ? FBB : TBB, nullptr, | ||||||||
1126 | NewCond, dl); | ||||||||
1127 | } | ||||||||
1128 | |||||||||
1129 | MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(*PBB), PBB)); | ||||||||
1130 | } | ||||||||
1131 | } | ||||||||
1132 | |||||||||
1133 | // If this is a large problem, avoid visiting the same basic blocks multiple | ||||||||
1134 | // times. | ||||||||
1135 | if (MergePotentials.size() == TailMergeThreshold) | ||||||||
1136 | for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i) | ||||||||
1137 | TriedMerging.insert(MergePotentials[i].getBlock()); | ||||||||
1138 | |||||||||
1139 | if (MergePotentials.size() >= 2) | ||||||||
1140 | MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength); | ||||||||
1141 | |||||||||
1142 | // Reinsert an unconditional branch if needed. The 1 below can occur as a | ||||||||
1143 | // result of removing blocks in TryTailMergeBlocks. | ||||||||
1144 | PredBB = &*std::prev(I); // this may have been changed in TryTailMergeBlocks | ||||||||
1145 | if (MergePotentials.size() == 1 && | ||||||||
1146 | MergePotentials.begin()->getBlock() != PredBB) | ||||||||
1147 | FixTail(MergePotentials.begin()->getBlock(), IBB, TII); | ||||||||
1148 | } | ||||||||
1149 | |||||||||
1150 | return MadeChange; | ||||||||
1151 | } | ||||||||
1152 | |||||||||
1153 | void BranchFolder::setCommonTailEdgeWeights(MachineBasicBlock &TailMBB) { | ||||||||
1154 | SmallVector<BlockFrequency, 2> EdgeFreqLs(TailMBB.succ_size()); | ||||||||
1155 | BlockFrequency AccumulatedMBBFreq; | ||||||||
1156 | |||||||||
1157 | // Aggregate edge frequency of successor edge j: | ||||||||
1158 | // edgeFreq(j) = sum (freq(bb) * edgeProb(bb, j)), | ||||||||
1159 | // where bb is a basic block that is in SameTails. | ||||||||
1160 | for (const auto &Src : SameTails) { | ||||||||
1161 | const MachineBasicBlock *SrcMBB = Src.getBlock(); | ||||||||
1162 | BlockFrequency BlockFreq = MBBFreqInfo.getBlockFreq(SrcMBB); | ||||||||
1163 | AccumulatedMBBFreq += BlockFreq; | ||||||||
1164 | |||||||||
1165 | // It is not necessary to recompute edge weights if TailBB has less than two | ||||||||
1166 | // successors. | ||||||||
1167 | if (TailMBB.succ_size() <= 1) | ||||||||
1168 | continue; | ||||||||
1169 | |||||||||
1170 | auto EdgeFreq = EdgeFreqLs.begin(); | ||||||||
1171 | |||||||||
1172 | for (auto SuccI = TailMBB.succ_begin(), SuccE = TailMBB.succ_end(); | ||||||||
1173 | SuccI != SuccE; ++SuccI, ++EdgeFreq) | ||||||||
1174 | *EdgeFreq += BlockFreq * MBPI.getEdgeProbability(SrcMBB, *SuccI); | ||||||||
1175 | } | ||||||||
1176 | |||||||||
1177 | MBBFreqInfo.setBlockFreq(&TailMBB, AccumulatedMBBFreq); | ||||||||
1178 | |||||||||
1179 | if (TailMBB.succ_size() <= 1) | ||||||||
1180 | return; | ||||||||
1181 | |||||||||
1182 | auto SumEdgeFreq = | ||||||||
1183 | std::accumulate(EdgeFreqLs.begin(), EdgeFreqLs.end(), BlockFrequency(0)) | ||||||||
1184 | .getFrequency(); | ||||||||
1185 | auto EdgeFreq = EdgeFreqLs.begin(); | ||||||||
1186 | |||||||||
1187 | if (SumEdgeFreq > 0) { | ||||||||
1188 | for (auto SuccI = TailMBB.succ_begin(), SuccE = TailMBB.succ_end(); | ||||||||
1189 | SuccI != SuccE; ++SuccI, ++EdgeFreq) { | ||||||||
1190 | auto Prob = BranchProbability::getBranchProbability( | ||||||||
1191 | EdgeFreq->getFrequency(), SumEdgeFreq); | ||||||||
1192 | TailMBB.setSuccProbability(SuccI, Prob); | ||||||||
1193 | } | ||||||||
1194 | } | ||||||||
1195 | } | ||||||||
1196 | |||||||||
1197 | //===----------------------------------------------------------------------===// | ||||||||
1198 | // Branch Optimization | ||||||||
1199 | //===----------------------------------------------------------------------===// | ||||||||
1200 | |||||||||
1201 | bool BranchFolder::OptimizeBranches(MachineFunction &MF) { | ||||||||
1202 | bool MadeChange = false; | ||||||||
1203 | |||||||||
1204 | // Make sure blocks are numbered in order | ||||||||
1205 | MF.RenumberBlocks(); | ||||||||
1206 | // Renumbering blocks alters EH scope membership, recalculate it. | ||||||||
1207 | EHScopeMembership = getEHScopeMembership(MF); | ||||||||
1208 | |||||||||
1209 | for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end(); | ||||||||
1210 | I != E; ) { | ||||||||
1211 | MachineBasicBlock *MBB = &*I++; | ||||||||
1212 | MadeChange |= OptimizeBlock(MBB); | ||||||||
1213 | |||||||||
1214 | // If it is dead, remove it. | ||||||||
1215 | if (MBB->pred_empty()) { | ||||||||
1216 | RemoveDeadBlock(MBB); | ||||||||
1217 | MadeChange = true; | ||||||||
1218 | ++NumDeadBlocks; | ||||||||
1219 | } | ||||||||
1220 | } | ||||||||
1221 | |||||||||
1222 | return MadeChange; | ||||||||
1223 | } | ||||||||
1224 | |||||||||
1225 | // Blocks should be considered empty if they contain only debug info; | ||||||||
1226 | // else the debug info would affect codegen. | ||||||||
1227 | static bool IsEmptyBlock(MachineBasicBlock *MBB) { | ||||||||
1228 | return MBB->getFirstNonDebugInstr() == MBB->end(); | ||||||||
1229 | } | ||||||||
1230 | |||||||||
1231 | // Blocks with only debug info and branches should be considered the same | ||||||||
1232 | // as blocks with only branches. | ||||||||
1233 | static bool IsBranchOnlyBlock(MachineBasicBlock *MBB) { | ||||||||
1234 | MachineBasicBlock::iterator I = MBB->getFirstNonDebugInstr(); | ||||||||
1235 | assert(I != MBB->end() && "empty block!")((I != MBB->end() && "empty block!") ? static_cast <void> (0) : __assert_fail ("I != MBB->end() && \"empty block!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1235, __PRETTY_FUNCTION__)); | ||||||||
1236 | return I->isBranch(); | ||||||||
1237 | } | ||||||||
1238 | |||||||||
1239 | /// IsBetterFallthrough - Return true if it would be clearly better to | ||||||||
1240 | /// fall-through to MBB1 than to fall through into MBB2. This has to return | ||||||||
1241 | /// a strict ordering, returning true for both (MBB1,MBB2) and (MBB2,MBB1) will | ||||||||
1242 | /// result in infinite loops. | ||||||||
1243 | static bool IsBetterFallthrough(MachineBasicBlock *MBB1, | ||||||||
1244 | MachineBasicBlock *MBB2) { | ||||||||
1245 | assert(MBB1 && MBB2 && "Unknown MachineBasicBlock")((MBB1 && MBB2 && "Unknown MachineBasicBlock" ) ? static_cast<void> (0) : __assert_fail ("MBB1 && MBB2 && \"Unknown MachineBasicBlock\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1245, __PRETTY_FUNCTION__)); | ||||||||
1246 | |||||||||
1247 | // Right now, we use a simple heuristic. If MBB2 ends with a call, and | ||||||||
1248 | // MBB1 doesn't, we prefer to fall through into MBB1. This allows us to | ||||||||
1249 | // optimize branches that branch to either a return block or an assert block | ||||||||
1250 | // into a fallthrough to the return. | ||||||||
1251 | MachineBasicBlock::iterator MBB1I = MBB1->getLastNonDebugInstr(); | ||||||||
1252 | MachineBasicBlock::iterator MBB2I = MBB2->getLastNonDebugInstr(); | ||||||||
1253 | if (MBB1I == MBB1->end() || MBB2I == MBB2->end()) | ||||||||
1254 | return false; | ||||||||
1255 | |||||||||
1256 | // If there is a clear successor ordering we make sure that one block | ||||||||
1257 | // will fall through to the next | ||||||||
1258 | if (MBB1->isSuccessor(MBB2)) return true; | ||||||||
1259 | if (MBB2->isSuccessor(MBB1)) return false; | ||||||||
1260 | |||||||||
1261 | return MBB2I->isCall() && !MBB1I->isCall(); | ||||||||
1262 | } | ||||||||
1263 | |||||||||
1264 | /// getBranchDebugLoc - Find and return, if any, the DebugLoc of the branch | ||||||||
1265 | /// instructions on the block. | ||||||||
1266 | static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB) { | ||||||||
1267 | MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr(); | ||||||||
1268 | if (I != MBB.end() && I->isBranch()) | ||||||||
1269 | return I->getDebugLoc(); | ||||||||
1270 | return DebugLoc(); | ||||||||
1271 | } | ||||||||
1272 | |||||||||
1273 | static void copyDebugInfoToPredecessor(const TargetInstrInfo *TII, | ||||||||
1274 | MachineBasicBlock &MBB, | ||||||||
1275 | MachineBasicBlock &PredMBB) { | ||||||||
1276 | auto InsertBefore = PredMBB.getFirstTerminator(); | ||||||||
1277 | for (MachineInstr &MI : MBB.instrs()) | ||||||||
1278 | if (MI.isDebugInstr()) { | ||||||||
1279 | TII->duplicate(PredMBB, InsertBefore, MI); | ||||||||
1280 | LLVM_DEBUG(dbgs() << "Copied debug entity from empty block to pred: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Copied debug entity from empty block to pred: " << MI; } } while (false) | ||||||||
1281 | << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Copied debug entity from empty block to pred: " << MI; } } while (false); | ||||||||
1282 | } | ||||||||
1283 | } | ||||||||
1284 | |||||||||
1285 | static void copyDebugInfoToSuccessor(const TargetInstrInfo *TII, | ||||||||
1286 | MachineBasicBlock &MBB, | ||||||||
1287 | MachineBasicBlock &SuccMBB) { | ||||||||
1288 | auto InsertBefore = SuccMBB.SkipPHIsAndLabels(SuccMBB.begin()); | ||||||||
1289 | for (MachineInstr &MI : MBB.instrs()) | ||||||||
1290 | if (MI.isDebugInstr()) { | ||||||||
1291 | TII->duplicate(SuccMBB, InsertBefore, MI); | ||||||||
1292 | LLVM_DEBUG(dbgs() << "Copied debug entity from empty block to succ: "do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Copied debug entity from empty block to succ: " << MI; } } while (false) | ||||||||
1293 | << MI)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "Copied debug entity from empty block to succ: " << MI; } } while (false); | ||||||||
1294 | } | ||||||||
1295 | } | ||||||||
1296 | |||||||||
1297 | // Try to salvage DBG_VALUE instructions from an otherwise empty block. If such | ||||||||
1298 | // a basic block is removed we would lose the debug information unless we have | ||||||||
1299 | // copied the information to a predecessor/successor. | ||||||||
1300 | // | ||||||||
1301 | // TODO: This function only handles some simple cases. An alternative would be | ||||||||
1302 | // to run a heavier analysis, such as the LiveDebugValues pass, before we do | ||||||||
1303 | // branch folding. | ||||||||
1304 | static void salvageDebugInfoFromEmptyBlock(const TargetInstrInfo *TII, | ||||||||
1305 | MachineBasicBlock &MBB) { | ||||||||
1306 | assert(IsEmptyBlock(&MBB) && "Expected an empty block (except debug info).")((IsEmptyBlock(&MBB) && "Expected an empty block (except debug info)." ) ? static_cast<void> (0) : __assert_fail ("IsEmptyBlock(&MBB) && \"Expected an empty block (except debug info).\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1306, __PRETTY_FUNCTION__)); | ||||||||
1307 | // If this MBB is the only predecessor of a successor it is legal to copy | ||||||||
1308 | // DBG_VALUE instructions to the beginning of the successor. | ||||||||
1309 | for (MachineBasicBlock *SuccBB : MBB.successors()) | ||||||||
1310 | if (SuccBB->pred_size() == 1) | ||||||||
1311 | copyDebugInfoToSuccessor(TII, MBB, *SuccBB); | ||||||||
1312 | // If this MBB is the only successor of a predecessor it is legal to copy the | ||||||||
1313 | // DBG_VALUE instructions to the end of the predecessor (just before the | ||||||||
1314 | // terminators, assuming that the terminator isn't affecting the DBG_VALUE). | ||||||||
1315 | for (MachineBasicBlock *PredBB : MBB.predecessors()) | ||||||||
1316 | if (PredBB->succ_size() == 1) | ||||||||
1317 | copyDebugInfoToPredecessor(TII, MBB, *PredBB); | ||||||||
1318 | } | ||||||||
1319 | |||||||||
1320 | bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) { | ||||||||
1321 | bool MadeChange = false; | ||||||||
1322 | MachineFunction &MF = *MBB->getParent(); | ||||||||
1323 | ReoptimizeBlock: | ||||||||
1324 | |||||||||
1325 | MachineFunction::iterator FallThrough = MBB->getIterator(); | ||||||||
1326 | ++FallThrough; | ||||||||
1327 | |||||||||
1328 | // Make sure MBB and FallThrough belong to the same EH scope. | ||||||||
1329 | bool SameEHScope = true; | ||||||||
1330 | if (!EHScopeMembership.empty() && FallThrough != MF.end()) { | ||||||||
| |||||||||
1331 | auto MBBEHScope = EHScopeMembership.find(MBB); | ||||||||
1332 | assert(MBBEHScope != EHScopeMembership.end())((MBBEHScope != EHScopeMembership.end()) ? static_cast<void > (0) : __assert_fail ("MBBEHScope != EHScopeMembership.end()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1332, __PRETTY_FUNCTION__)); | ||||||||
1333 | auto FallThroughEHScope = EHScopeMembership.find(&*FallThrough); | ||||||||
1334 | assert(FallThroughEHScope != EHScopeMembership.end())((FallThroughEHScope != EHScopeMembership.end()) ? static_cast <void> (0) : __assert_fail ("FallThroughEHScope != EHScopeMembership.end()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1334, __PRETTY_FUNCTION__)); | ||||||||
1335 | SameEHScope = MBBEHScope->second == FallThroughEHScope->second; | ||||||||
1336 | } | ||||||||
1337 | |||||||||
1338 | // If this block is empty, make everyone use its fall-through, not the block | ||||||||
1339 | // explicitly. Landing pads should not do this since the landing-pad table | ||||||||
1340 | // points to this block. Blocks with their addresses taken shouldn't be | ||||||||
1341 | // optimized away. | ||||||||
1342 | if (IsEmptyBlock(MBB) && !MBB->isEHPad() && !MBB->hasAddressTaken() && | ||||||||
1343 | SameEHScope) { | ||||||||
1344 | salvageDebugInfoFromEmptyBlock(TII, *MBB); | ||||||||
1345 | // Dead block? Leave for cleanup later. | ||||||||
1346 | if (MBB->pred_empty()) return MadeChange; | ||||||||
1347 | |||||||||
1348 | if (FallThrough == MF.end()) { | ||||||||
1349 | // TODO: Simplify preds to not branch here if possible! | ||||||||
1350 | } else if (FallThrough->isEHPad()) { | ||||||||
1351 | // Don't rewrite to a landing pad fallthough. That could lead to the case | ||||||||
1352 | // where a BB jumps to more than one landing pad. | ||||||||
1353 | // TODO: Is it ever worth rewriting predecessors which don't already | ||||||||
1354 | // jump to a landing pad, and so can safely jump to the fallthrough? | ||||||||
1355 | } else if (MBB->isSuccessor(&*FallThrough)) { | ||||||||
1356 | // Rewrite all predecessors of the old block to go to the fallthrough | ||||||||
1357 | // instead. | ||||||||
1358 | while (!MBB->pred_empty()) { | ||||||||
1359 | MachineBasicBlock *Pred = *(MBB->pred_end()-1); | ||||||||
1360 | Pred->ReplaceUsesOfBlockWith(MBB, &*FallThrough); | ||||||||
1361 | } | ||||||||
1362 | // If MBB was the target of a jump table, update jump tables to go to the | ||||||||
1363 | // fallthrough instead. | ||||||||
1364 | if (MachineJumpTableInfo *MJTI = MF.getJumpTableInfo()) | ||||||||
1365 | MJTI->ReplaceMBBInJumpTables(MBB, &*FallThrough); | ||||||||
1366 | MadeChange = true; | ||||||||
1367 | } | ||||||||
1368 | return MadeChange; | ||||||||
1369 | } | ||||||||
1370 | |||||||||
1371 | // Check to see if we can simplify the terminator of the block before this | ||||||||
1372 | // one. | ||||||||
1373 | MachineBasicBlock &PrevBB = *std::prev(MachineFunction::iterator(MBB)); | ||||||||
1374 | |||||||||
1375 | MachineBasicBlock *PriorTBB = nullptr, *PriorFBB = nullptr; | ||||||||
1376 | SmallVector<MachineOperand, 4> PriorCond; | ||||||||
1377 | bool PriorUnAnalyzable = | ||||||||
1378 | TII->analyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, true); | ||||||||
1379 | if (!PriorUnAnalyzable) { | ||||||||
1380 | // If the CFG for the prior block has extra edges, remove them. | ||||||||
1381 | MadeChange |= PrevBB.CorrectExtraCFGEdges(PriorTBB, PriorFBB, | ||||||||
1382 | !PriorCond.empty()); | ||||||||
1383 | |||||||||
1384 | // If the previous branch is conditional and both conditions go to the same | ||||||||
1385 | // destination, remove the branch, replacing it with an unconditional one or | ||||||||
1386 | // a fall-through. | ||||||||
1387 | if (PriorTBB && PriorTBB == PriorFBB) { | ||||||||
1388 | DebugLoc dl = getBranchDebugLoc(PrevBB); | ||||||||
1389 | TII->removeBranch(PrevBB); | ||||||||
1390 | PriorCond.clear(); | ||||||||
1391 | if (PriorTBB != MBB) | ||||||||
1392 | TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl); | ||||||||
1393 | MadeChange = true; | ||||||||
1394 | ++NumBranchOpts; | ||||||||
1395 | goto ReoptimizeBlock; | ||||||||
1396 | } | ||||||||
1397 | |||||||||
1398 | // If the previous block unconditionally falls through to this block and | ||||||||
1399 | // this block has no other predecessors, move the contents of this block | ||||||||
1400 | // into the prior block. This doesn't usually happen when SimplifyCFG | ||||||||
1401 | // has been used, but it can happen if tail merging splits a fall-through | ||||||||
1402 | // predecessor of a block. | ||||||||
1403 | // This has to check PrevBB->succ_size() because EH edges are ignored by | ||||||||
1404 | // analyzeBranch. | ||||||||
1405 | if (PriorCond.empty() && !PriorTBB && MBB->pred_size() == 1 && | ||||||||
1406 | PrevBB.succ_size() == 1 && | ||||||||
1407 | !MBB->hasAddressTaken() && !MBB->isEHPad()) { | ||||||||
1408 | LLVM_DEBUG(dbgs() << "\nMerging into block: " << PrevBBdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nMerging into block: " << PrevBB << "From MBB: " << *MBB; } } while (false) | ||||||||
1409 | << "From MBB: " << *MBB)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nMerging into block: " << PrevBB << "From MBB: " << *MBB; } } while (false); | ||||||||
1410 | // Remove redundant DBG_VALUEs first. | ||||||||
1411 | if (PrevBB.begin() != PrevBB.end()) { | ||||||||
1412 | MachineBasicBlock::iterator PrevBBIter = PrevBB.end(); | ||||||||
1413 | --PrevBBIter; | ||||||||
1414 | MachineBasicBlock::iterator MBBIter = MBB->begin(); | ||||||||
1415 | // Check if DBG_VALUE at the end of PrevBB is identical to the | ||||||||
1416 | // DBG_VALUE at the beginning of MBB. | ||||||||
1417 | while (PrevBBIter != PrevBB.begin() && MBBIter != MBB->end() | ||||||||
1418 | && PrevBBIter->isDebugInstr() && MBBIter->isDebugInstr()) { | ||||||||
1419 | if (!MBBIter->isIdenticalTo(*PrevBBIter)) | ||||||||
1420 | break; | ||||||||
1421 | MachineInstr &DuplicateDbg = *MBBIter; | ||||||||
1422 | ++MBBIter; -- PrevBBIter; | ||||||||
1423 | DuplicateDbg.eraseFromParent(); | ||||||||
1424 | } | ||||||||
1425 | } | ||||||||
1426 | PrevBB.splice(PrevBB.end(), MBB, MBB->begin(), MBB->end()); | ||||||||
1427 | PrevBB.removeSuccessor(PrevBB.succ_begin()); | ||||||||
1428 | assert(PrevBB.succ_empty())((PrevBB.succ_empty()) ? static_cast<void> (0) : __assert_fail ("PrevBB.succ_empty()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1428, __PRETTY_FUNCTION__)); | ||||||||
1429 | PrevBB.transferSuccessors(MBB); | ||||||||
1430 | MadeChange = true; | ||||||||
1431 | return MadeChange; | ||||||||
1432 | } | ||||||||
1433 | |||||||||
1434 | // If the previous branch *only* branches to *this* block (conditional or | ||||||||
1435 | // not) remove the branch. | ||||||||
1436 | if (PriorTBB
| ||||||||
1437 | TII->removeBranch(PrevBB); | ||||||||
1438 | MadeChange = true; | ||||||||
1439 | ++NumBranchOpts; | ||||||||
1440 | goto ReoptimizeBlock; | ||||||||
1441 | } | ||||||||
1442 | |||||||||
1443 | // If the prior block branches somewhere else on the condition and here if | ||||||||
1444 | // the condition is false, remove the uncond second branch. | ||||||||
1445 | if (PriorFBB == MBB) { | ||||||||
1446 | DebugLoc dl = getBranchDebugLoc(PrevBB); | ||||||||
1447 | TII->removeBranch(PrevBB); | ||||||||
1448 | TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl); | ||||||||
1449 | MadeChange = true; | ||||||||
1450 | ++NumBranchOpts; | ||||||||
1451 | goto ReoptimizeBlock; | ||||||||
1452 | } | ||||||||
1453 | |||||||||
1454 | // If the prior block branches here on true and somewhere else on false, and | ||||||||
1455 | // if the branch condition is reversible, reverse the branch to create a | ||||||||
1456 | // fall-through. | ||||||||
1457 | if (PriorTBB
| ||||||||
1458 | SmallVector<MachineOperand, 4> NewPriorCond(PriorCond); | ||||||||
1459 | if (!TII->reverseBranchCondition(NewPriorCond)) { | ||||||||
1460 | DebugLoc dl = getBranchDebugLoc(PrevBB); | ||||||||
1461 | TII->removeBranch(PrevBB); | ||||||||
1462 | TII->insertBranch(PrevBB, PriorFBB, nullptr, NewPriorCond, dl); | ||||||||
1463 | MadeChange = true; | ||||||||
1464 | ++NumBranchOpts; | ||||||||
1465 | goto ReoptimizeBlock; | ||||||||
1466 | } | ||||||||
1467 | } | ||||||||
1468 | |||||||||
1469 | // If this block has no successors (e.g. it is a return block or ends with | ||||||||
1470 | // a call to a no-return function like abort or __cxa_throw) and if the pred | ||||||||
1471 | // falls through into this block, and if it would otherwise fall through | ||||||||
1472 | // into the block after this, move this block to the end of the function. | ||||||||
1473 | // | ||||||||
1474 | // We consider it more likely that execution will stay in the function (e.g. | ||||||||
1475 | // due to loops) than it is to exit it. This asserts in loops etc, moving | ||||||||
1476 | // the assert condition out of the loop body. | ||||||||
1477 | if (MBB->succ_empty() && !PriorCond.empty() && !PriorFBB && | ||||||||
1478 | MachineFunction::iterator(PriorTBB) == FallThrough && | ||||||||
1479 | !MBB->canFallThrough()) { | ||||||||
1480 | bool DoTransform = true; | ||||||||
1481 | |||||||||
1482 | // We have to be careful that the succs of PredBB aren't both no-successor | ||||||||
1483 | // blocks. If neither have successors and if PredBB is the second from | ||||||||
1484 | // last block in the function, we'd just keep swapping the two blocks for | ||||||||
1485 | // last. Only do the swap if one is clearly better to fall through than | ||||||||
1486 | // the other. | ||||||||
1487 | if (FallThrough == --MF.end() && | ||||||||
1488 | !IsBetterFallthrough(PriorTBB, MBB)) | ||||||||
1489 | DoTransform = false; | ||||||||
1490 | |||||||||
1491 | if (DoTransform
| ||||||||
1492 | // Reverse the branch so we will fall through on the previous true cond. | ||||||||
1493 | SmallVector<MachineOperand, 4> NewPriorCond(PriorCond); | ||||||||
1494 | if (!TII->reverseBranchCondition(NewPriorCond)) { | ||||||||
1495 | LLVM_DEBUG(dbgs() << "\nMoving MBB: " << *MBBdo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nMoving MBB: " << *MBB << "To make fallthrough to: " << *PriorTBB << "\n"; } } while (false) | ||||||||
| |||||||||
1496 | << "To make fallthrough to: " << *PriorTBB << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType ("branch-folder")) { dbgs() << "\nMoving MBB: " << *MBB << "To make fallthrough to: " << *PriorTBB << "\n"; } } while (false); | ||||||||
1497 | |||||||||
1498 | DebugLoc dl = getBranchDebugLoc(PrevBB); | ||||||||
1499 | TII->removeBranch(PrevBB); | ||||||||
1500 | TII->insertBranch(PrevBB, MBB, nullptr, NewPriorCond, dl); | ||||||||
1501 | |||||||||
1502 | // Move this block to the end of the function. | ||||||||
1503 | MBB->moveAfter(&MF.back()); | ||||||||
1504 | MadeChange = true; | ||||||||
1505 | ++NumBranchOpts; | ||||||||
1506 | return MadeChange; | ||||||||
1507 | } | ||||||||
1508 | } | ||||||||
1509 | } | ||||||||
1510 | } | ||||||||
1511 | |||||||||
1512 | bool OptForSize = | ||||||||
1513 | MF.getFunction().hasOptSize() || | ||||||||
1514 | llvm::shouldOptimizeForSize(MBB, PSI, &MBBFreqInfo); | ||||||||
1515 | if (!IsEmptyBlock(MBB) && MBB->pred_size() == 1 && OptForSize) { | ||||||||
1516 | // Changing "Jcc foo; foo: jmp bar;" into "Jcc bar;" might change the branch | ||||||||
1517 | // direction, thereby defeating careful block placement and regressing | ||||||||
1518 | // performance. Therefore, only consider this for optsize functions. | ||||||||
1519 | MachineInstr &TailCall = *MBB->getFirstNonDebugInstr(); | ||||||||
1520 | if (TII->isUnconditionalTailCall(TailCall)) { | ||||||||
1521 | MachineBasicBlock *Pred = *MBB->pred_begin(); | ||||||||
1522 | MachineBasicBlock *PredTBB = nullptr, *PredFBB = nullptr; | ||||||||
1523 | SmallVector<MachineOperand, 4> PredCond; | ||||||||
1524 | bool PredAnalyzable = | ||||||||
1525 | !TII->analyzeBranch(*Pred, PredTBB, PredFBB, PredCond, true); | ||||||||
1526 | |||||||||
1527 | if (PredAnalyzable && !PredCond.empty() && PredTBB == MBB && | ||||||||
1528 | PredTBB != PredFBB) { | ||||||||
1529 | // The predecessor has a conditional branch to this block which consists | ||||||||
1530 | // of only a tail call. Try to fold the tail call into the conditional | ||||||||
1531 | // branch. | ||||||||
1532 | if (TII->canMakeTailCallConditional(PredCond, TailCall)) { | ||||||||
1533 | // TODO: It would be nice if analyzeBranch() could provide a pointer | ||||||||
1534 | // to the branch instruction so replaceBranchWithTailCall() doesn't | ||||||||
1535 | // have to search for it. | ||||||||
1536 | TII->replaceBranchWithTailCall(*Pred, PredCond, TailCall); | ||||||||
1537 | ++NumTailCalls; | ||||||||
1538 | Pred->removeSuccessor(MBB); | ||||||||
1539 | MadeChange = true; | ||||||||
1540 | return MadeChange; | ||||||||
1541 | } | ||||||||
1542 | } | ||||||||
1543 | // If the predecessor is falling through to this block, we could reverse | ||||||||
1544 | // the branch condition and fold the tail call into that. However, after | ||||||||
1545 | // that we might have to re-arrange the CFG to fall through to the other | ||||||||
1546 | // block and there is a high risk of regressing code size rather than | ||||||||
1547 | // improving it. | ||||||||
1548 | } | ||||||||
1549 | } | ||||||||
1550 | |||||||||
1551 | // Analyze the branch in the current block. | ||||||||
1552 | MachineBasicBlock *CurTBB = nullptr, *CurFBB = nullptr; | ||||||||
1553 | SmallVector<MachineOperand, 4> CurCond; | ||||||||
1554 | bool CurUnAnalyzable = | ||||||||
1555 | TII->analyzeBranch(*MBB, CurTBB, CurFBB, CurCond, true); | ||||||||
1556 | if (!CurUnAnalyzable) { | ||||||||
1557 | // If the CFG for the prior block has extra edges, remove them. | ||||||||
1558 | MadeChange |= MBB->CorrectExtraCFGEdges(CurTBB, CurFBB, !CurCond.empty()); | ||||||||
1559 | |||||||||
1560 | // If this is a two-way branch, and the FBB branches to this block, reverse | ||||||||
1561 | // the condition so the single-basic-block loop is faster. Instead of: | ||||||||
1562 | // Loop: xxx; jcc Out; jmp Loop | ||||||||
1563 | // we want: | ||||||||
1564 | // Loop: xxx; jncc Loop; jmp Out | ||||||||
1565 | if (CurTBB && CurFBB && CurFBB == MBB && CurTBB != MBB) { | ||||||||
1566 | SmallVector<MachineOperand, 4> NewCond(CurCond); | ||||||||
1567 | if (!TII->reverseBranchCondition(NewCond)) { | ||||||||
1568 | DebugLoc dl = getBranchDebugLoc(*MBB); | ||||||||
1569 | TII->removeBranch(*MBB); | ||||||||
1570 | TII->insertBranch(*MBB, CurFBB, CurTBB, NewCond, dl); | ||||||||
1571 | MadeChange = true; | ||||||||
1572 | ++NumBranchOpts; | ||||||||
1573 | goto ReoptimizeBlock; | ||||||||
1574 | } | ||||||||
1575 | } | ||||||||
1576 | |||||||||
1577 | // If this branch is the only thing in its block, see if we can forward | ||||||||
1578 | // other blocks across it. | ||||||||
1579 | if (CurTBB && CurCond.empty() && !CurFBB && | ||||||||
1580 | IsBranchOnlyBlock(MBB) && CurTBB != MBB && | ||||||||
1581 | !MBB->hasAddressTaken() && !MBB->isEHPad()) { | ||||||||
1582 | DebugLoc dl = getBranchDebugLoc(*MBB); | ||||||||
1583 | // This block may contain just an unconditional branch. Because there can | ||||||||
1584 | // be 'non-branch terminators' in the block, try removing the branch and | ||||||||
1585 | // then seeing if the block is empty. | ||||||||
1586 | TII->removeBranch(*MBB); | ||||||||
1587 | // If the only things remaining in the block are debug info, remove these | ||||||||
1588 | // as well, so this will behave the same as an empty block in non-debug | ||||||||
1589 | // mode. | ||||||||
1590 | if (IsEmptyBlock(MBB)) { | ||||||||
1591 | // Make the block empty, losing the debug info (we could probably | ||||||||
1592 | // improve this in some cases.) | ||||||||
1593 | MBB->erase(MBB->begin(), MBB->end()); | ||||||||
1594 | } | ||||||||
1595 | // If this block is just an unconditional branch to CurTBB, we can | ||||||||
1596 | // usually completely eliminate the block. The only case we cannot | ||||||||
1597 | // completely eliminate the block is when the block before this one | ||||||||
1598 | // falls through into MBB and we can't understand the prior block's branch | ||||||||
1599 | // condition. | ||||||||
1600 | if (MBB->empty()) { | ||||||||
1601 | bool PredHasNoFallThrough = !PrevBB.canFallThrough(); | ||||||||
1602 | if (PredHasNoFallThrough || !PriorUnAnalyzable || | ||||||||
1603 | !PrevBB.isSuccessor(MBB)) { | ||||||||
1604 | // If the prior block falls through into us, turn it into an | ||||||||
1605 | // explicit branch to us to make updates simpler. | ||||||||
1606 | if (!PredHasNoFallThrough && PrevBB.isSuccessor(MBB) && | ||||||||
1607 | PriorTBB != MBB && PriorFBB != MBB) { | ||||||||
1608 | if (!PriorTBB) { | ||||||||
1609 | assert(PriorCond.empty() && !PriorFBB &&((PriorCond.empty() && !PriorFBB && "Bad branch analysis" ) ? static_cast<void> (0) : __assert_fail ("PriorCond.empty() && !PriorFBB && \"Bad branch analysis\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1610, __PRETTY_FUNCTION__)) | ||||||||
1610 | "Bad branch analysis")((PriorCond.empty() && !PriorFBB && "Bad branch analysis" ) ? static_cast<void> (0) : __assert_fail ("PriorCond.empty() && !PriorFBB && \"Bad branch analysis\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1610, __PRETTY_FUNCTION__)); | ||||||||
1611 | PriorTBB = MBB; | ||||||||
1612 | } else { | ||||||||
1613 | assert(!PriorFBB && "Machine CFG out of date!")((!PriorFBB && "Machine CFG out of date!") ? static_cast <void> (0) : __assert_fail ("!PriorFBB && \"Machine CFG out of date!\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/lib/CodeGen/BranchFolding.cpp" , 1613, __PRETTY_FUNCTION__)); | ||||||||
1614 | PriorFBB = MBB; | ||||||||
1615 | } | ||||||||
1616 | DebugLoc pdl = getBranchDebugLoc(PrevBB); | ||||||||
1617 | TII->removeBranch(PrevBB); | ||||||||
1618 | TII->insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl); | ||||||||
1619 | } | ||||||||
1620 | |||||||||
1621 | // Iterate through all the predecessors, revectoring each in-turn. | ||||||||
1622 | size_t PI = 0; | ||||||||
1623 | bool DidChange = false; | ||||||||
1624 | bool HasBranchToSelf = false; | ||||||||
1625 | while(PI != MBB->pred_size()) { | ||||||||
1626 | MachineBasicBlock *PMBB = *(MBB->pred_begin() + PI); | ||||||||
1627 | if (PMBB == MBB) { | ||||||||
1628 | // If this block has an uncond branch to itself, leave it. | ||||||||
1629 | ++PI; | ||||||||
1630 | HasBranchToSelf = true; | ||||||||
1631 | } else { | ||||||||
1632 | DidChange = true; | ||||||||
1633 | PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB); | ||||||||
1634 | // If this change resulted in PMBB ending in a conditional | ||||||||
1635 | // branch where both conditions go to the same destination, | ||||||||
1636 | // change this to an unconditional branch (and fix the CFG). | ||||||||
1637 | MachineBasicBlock *NewCurTBB = nullptr, *NewCurFBB = nullptr; | ||||||||
1638 | SmallVector<MachineOperand, 4> NewCurCond; | ||||||||
1639 | bool NewCurUnAnalyzable = TII->analyzeBranch( | ||||||||
1640 | *PMBB, NewCurTBB, NewCurFBB, NewCurCond, true); | ||||||||
1641 | if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) { | ||||||||
1642 | DebugLoc pdl = getBranchDebugLoc(*PMBB); | ||||||||
1643 | TII->removeBranch(*PMBB); | ||||||||
1644 | NewCurCond.clear(); | ||||||||
1645 | TII->insertBranch(*PMBB, NewCurTBB, nullptr, NewCurCond, pdl); | ||||||||
1646 | MadeChange = true; | ||||||||
1647 | ++NumBranchOpts; | ||||||||
1648 | PMBB->CorrectExtraCFGEdges(NewCurTBB, nullptr, false); | ||||||||
1649 | } | ||||||||
1650 | } | ||||||||
1651 | } | ||||||||
1652 | |||||||||
1653 | // Change any jumptables to go to the new MBB. | ||||||||
1654 | if (MachineJumpTableInfo *MJTI = MF.getJumpTableInfo()) | ||||||||
1655 | MJTI->ReplaceMBBInJumpTables(MBB, CurTBB); | ||||||||
1656 | if (DidChange) { | ||||||||
1657 | ++NumBranchOpts; | ||||||||
1658 | MadeChange = true; | ||||||||
1659 | if (!HasBranchToSelf) return MadeChange; | ||||||||
1660 | } | ||||||||
1661 | } | ||||||||
1662 | } | ||||||||
1663 | |||||||||
1664 | // Add the branch back if the block is more than just an uncond branch. | ||||||||
1665 | TII->insertBranch(*MBB, CurTBB, nullptr, CurCond, dl); | ||||||||
1666 | } | ||||||||
1667 | } | ||||||||
1668 | |||||||||
1669 | // If the prior block doesn't fall through into this block, and if this | ||||||||
1670 | // block doesn't fall through into some other block, see if we can find a | ||||||||
1671 | // place to move this block where a fall-through will happen. | ||||||||
1672 | if (!PrevBB.canFallThrough()) { | ||||||||
1673 | // Now we know that there was no fall-through into this block, check to | ||||||||
1674 | // see if it has a fall-through into its successor. | ||||||||
1675 | bool CurFallsThru = MBB->canFallThrough(); | ||||||||
1676 | |||||||||
1677 | if (!MBB->isEHPad()) { | ||||||||
1678 | // Check all the predecessors of this block. If one of them has no fall | ||||||||
1679 | // throughs, move this block right after it. | ||||||||
1680 | for (MachineBasicBlock *PredBB : MBB->predecessors()) { | ||||||||
1681 | // Analyze the branch at the end of the pred. | ||||||||
1682 | MachineBasicBlock *PredTBB = nullptr, *PredFBB = nullptr; | ||||||||
1683 | SmallVector<MachineOperand, 4> PredCond; | ||||||||
1684 | if (PredBB != MBB && !PredBB->canFallThrough() && | ||||||||
1685 | !TII->analyzeBranch(*PredBB, PredTBB, PredFBB, PredCond, true) && | ||||||||
1686 | (!CurFallsThru || !CurTBB || !CurFBB) && | ||||||||
1687 | (!CurFallsThru || MBB->getNumber() >= PredBB->getNumber())) { | ||||||||
1688 | // If the current block doesn't fall through, just move it. | ||||||||
1689 | // If the current block can fall through and does not end with a | ||||||||
1690 | // conditional branch, we need to append an unconditional jump to | ||||||||
1691 | // the (current) next block. To avoid a possible compile-time | ||||||||
1692 | // infinite loop, move blocks only backward in this case. | ||||||||
1693 | // Also, if there are already 2 branches here, we cannot add a third; | ||||||||
1694 | // this means we have the case | ||||||||
1695 | // Bcc next | ||||||||
1696 | // B elsewhere | ||||||||
1697 | // next: | ||||||||
1698 | if (CurFallsThru) { | ||||||||
1699 | MachineBasicBlock *NextBB = &*std::next(MBB->getIterator()); | ||||||||
1700 | CurCond.clear(); | ||||||||
1701 | TII->insertBranch(*MBB, NextBB, nullptr, CurCond, DebugLoc()); | ||||||||
1702 | } | ||||||||
1703 | MBB->moveAfter(PredBB); | ||||||||
1704 | MadeChange = true; | ||||||||
1705 | goto ReoptimizeBlock; | ||||||||
1706 | } | ||||||||
1707 | } | ||||||||
1708 | } | ||||||||
1709 | |||||||||
1710 | if (!CurFallsThru) { | ||||||||
1711 | // Check all successors to see if we can move this block before it. | ||||||||
1712 | for (MachineBasicBlock *SuccBB : MBB->successors()) { | ||||||||
1713 | // Analyze the branch at the end of the block before the succ. | ||||||||
1714 | MachineFunction::iterator SuccPrev = --SuccBB->getIterator(); | ||||||||
1715 | |||||||||
1716 | // If this block doesn't already fall-through to that successor, and if | ||||||||
1717 | // the succ doesn't already have a block that can fall through into it, | ||||||||
1718 | // and if the successor isn't an EH destination, we can arrange for the | ||||||||
1719 | // fallthrough to happen. | ||||||||
1720 | if (SuccBB != MBB && &*SuccPrev != MBB && | ||||||||
1721 | !SuccPrev->canFallThrough() && !CurUnAnalyzable && | ||||||||
1722 | !SuccBB->isEHPad()) { | ||||||||
1723 | MBB->moveBefore(SuccBB); | ||||||||
1724 | MadeChange = true; | ||||||||
1725 | goto ReoptimizeBlock; | ||||||||
1726 | } | ||||||||
1727 | } | ||||||||
1728 | |||||||||
1729 | // Okay, there is no really great place to put this block. If, however, | ||||||||
1730 | // the block before this one would be a fall-through if this block were | ||||||||
1731 | // removed, move this block to the end of the function. There is no real | ||||||||
1732 | // advantage in "falling through" to an EH block, so we don't want to | ||||||||
1733 | // perform this transformation for that case. | ||||||||
1734 | // | ||||||||
1735 | // Also, Windows EH introduced the possibility of an arbitrary number of | ||||||||
1736 | // successors to a given block. The analyzeBranch call does not consider | ||||||||
1737 | // exception handling and so we can get in a state where a block | ||||||||
1738 | // containing a call is followed by multiple EH blocks that would be | ||||||||
1739 | // rotated infinitely at the end of the function if the transformation | ||||||||
1740 | // below were performed for EH "FallThrough" blocks. Therefore, even if | ||||||||
1741 | // that appears not to be happening anymore, we should assume that it is | ||||||||
1742 | // possible and not remove the "!FallThrough()->isEHPad" condition below. | ||||||||
1743 | MachineBasicBlock *PrevTBB = nullptr, *PrevFBB = nullptr; | ||||||||
1744 | SmallVector<MachineOperand, 4> PrevCond; | ||||||||
1745 | if (FallThrough != MF.end() && | ||||||||
1746 | !FallThrough->isEHPad() && | ||||||||
1747 | !TII->analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond, true) && | ||||||||
1748 | PrevBB.isSuccessor(&*FallThrough)) { | ||||||||
1749 | MBB->moveAfter(&MF.back()); | ||||||||
1750 | MadeChange = true; | ||||||||
1751 | return MadeChange; | ||||||||
1752 | } | ||||||||
1753 | } | ||||||||
1754 | } | ||||||||
1755 | |||||||||
1756 | return MadeChange; | ||||||||
1757 | } | ||||||||
1758 | |||||||||
1759 | //===----------------------------------------------------------------------===// | ||||||||
1760 | // Hoist Common Code | ||||||||
1761 | //===----------------------------------------------------------------------===// | ||||||||
1762 | |||||||||
1763 | bool BranchFolder::HoistCommonCode(MachineFunction &MF) { | ||||||||
1764 | bool MadeChange = false; | ||||||||
1765 | for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ) { | ||||||||
1766 | MachineBasicBlock *MBB = &*I++; | ||||||||
1767 | MadeChange |= HoistCommonCodeInSuccs(MBB); | ||||||||
1768 | } | ||||||||
1769 | |||||||||
1770 | return MadeChange; | ||||||||
1771 | } | ||||||||
1772 | |||||||||
1773 | /// findFalseBlock - BB has a fallthrough. Find its 'false' successor given | ||||||||
1774 | /// its 'true' successor. | ||||||||
1775 | static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB, | ||||||||
1776 | MachineBasicBlock *TrueBB) { | ||||||||
1777 | for (MachineBasicBlock *SuccBB : BB->successors()) | ||||||||
1778 | if (SuccBB != TrueBB) | ||||||||
1779 | return SuccBB; | ||||||||
1780 | return nullptr; | ||||||||
1781 | } | ||||||||
1782 | |||||||||
1783 | template <class Container> | ||||||||
1784 | static void addRegAndItsAliases(unsigned Reg, const TargetRegisterInfo *TRI, | ||||||||
1785 | Container &Set) { | ||||||||
1786 | if (Register::isPhysicalRegister(Reg)) { | ||||||||
1787 | for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) | ||||||||
1788 | Set.insert(*AI); | ||||||||
1789 | } else { | ||||||||
1790 | Set.insert(Reg); | ||||||||
1791 | } | ||||||||
1792 | } | ||||||||
1793 | |||||||||
1794 | /// findHoistingInsertPosAndDeps - Find the location to move common instructions | ||||||||
1795 | /// in successors to. The location is usually just before the terminator, | ||||||||
1796 | /// however if the terminator is a conditional branch and its previous | ||||||||
1797 | /// instruction is the flag setting instruction, the previous instruction is | ||||||||
1798 | /// the preferred location. This function also gathers uses and defs of the | ||||||||
1799 | /// instructions from the insertion point to the end of the block. The data is | ||||||||
1800 | /// used by HoistCommonCodeInSuccs to ensure safety. | ||||||||
1801 | static | ||||||||
1802 | MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB, | ||||||||
1803 | const TargetInstrInfo *TII, | ||||||||
1804 | const TargetRegisterInfo *TRI, | ||||||||
1805 | SmallSet<unsigned,4> &Uses, | ||||||||
1806 | SmallSet<unsigned,4> &Defs) { | ||||||||
1807 | MachineBasicBlock::iterator Loc = MBB->getFirstTerminator(); | ||||||||
1808 | if (!TII->isUnpredicatedTerminator(*Loc)) | ||||||||
1809 | return MBB->end(); | ||||||||
1810 | |||||||||
1811 | for (const MachineOperand &MO : Loc->operands()) { | ||||||||
1812 | if (!MO.isReg()) | ||||||||
1813 | continue; | ||||||||
1814 | Register Reg = MO.getReg(); | ||||||||
1815 | if (!Reg) | ||||||||
1816 | continue; | ||||||||
1817 | if (MO.isUse()) { | ||||||||
1818 | addRegAndItsAliases(Reg, TRI, Uses); | ||||||||
1819 | } else { | ||||||||
1820 | if (!MO.isDead()) | ||||||||
1821 | // Don't try to hoist code in the rare case the terminator defines a | ||||||||
1822 | // register that is later used. | ||||||||
1823 | return MBB->end(); | ||||||||
1824 | |||||||||
1825 | // If the terminator defines a register, make sure we don't hoist | ||||||||
1826 | // the instruction whose def might be clobbered by the terminator. | ||||||||
1827 | addRegAndItsAliases(Reg, TRI, Defs); | ||||||||
1828 | } | ||||||||
1829 | } | ||||||||
1830 | |||||||||
1831 | if (Uses.empty()) | ||||||||
1832 | return Loc; | ||||||||
1833 | // If the terminator is the only instruction in the block and Uses is not | ||||||||
1834 | // empty (or we would have returned above), we can still safely hoist | ||||||||
1835 | // instructions just before the terminator as long as the Defs/Uses are not | ||||||||
1836 | // violated (which is checked in HoistCommonCodeInSuccs). | ||||||||
1837 | if (Loc == MBB->begin()) | ||||||||
1838 | return Loc; | ||||||||
1839 | |||||||||
1840 | // The terminator is probably a conditional branch, try not to separate the | ||||||||
1841 | // branch from condition setting instruction. | ||||||||
1842 | MachineBasicBlock::iterator PI = | ||||||||
1843 | skipDebugInstructionsBackward(std::prev(Loc), MBB->begin()); | ||||||||
1844 | |||||||||
1845 | bool IsDef = false; | ||||||||
1846 | for (const MachineOperand &MO : PI->operands()) { | ||||||||
1847 | // If PI has a regmask operand, it is probably a call. Separate away. | ||||||||
1848 | if (MO.isRegMask()) | ||||||||
1849 | return Loc; | ||||||||
1850 | if (!MO.isReg() || MO.isUse()) | ||||||||
1851 | continue; | ||||||||
1852 | Register Reg = MO.getReg(); | ||||||||
1853 | if (!Reg) | ||||||||
1854 | continue; | ||||||||
1855 | if (Uses.count(Reg)) { | ||||||||
1856 | IsDef = true; | ||||||||
1857 | break; | ||||||||
1858 | } | ||||||||
1859 | } | ||||||||
1860 | if (!IsDef) | ||||||||
1861 | // The condition setting instruction is not just before the conditional | ||||||||
1862 | // branch. | ||||||||
1863 | return Loc; | ||||||||
1864 | |||||||||
1865 | // Be conservative, don't insert instruction above something that may have | ||||||||
1866 | // side-effects. And since it's potentially bad to separate flag setting | ||||||||
1867 | // instruction from the conditional branch, just abort the optimization | ||||||||
1868 | // completely. | ||||||||
1869 | // Also avoid moving code above predicated instruction since it's hard to | ||||||||
1870 | // reason about register liveness with predicated instruction. | ||||||||
1871 | bool DontMoveAcrossStore = true; | ||||||||
1872 | if (!PI->isSafeToMove(nullptr, DontMoveAcrossStore) || TII->isPredicated(*PI)) | ||||||||
1873 | return MBB->end(); | ||||||||
1874 | |||||||||
1875 | // Find out what registers are live. Note this routine is ignoring other live | ||||||||
1876 | // registers which are only used by instructions in successor blocks. | ||||||||
1877 | for (const MachineOperand &MO : PI->operands()) { | ||||||||
1878 | if (!MO.isReg()) | ||||||||
1879 | continue; | ||||||||
1880 | Register Reg = MO.getReg(); | ||||||||
1881 | if (!Reg) | ||||||||
1882 | continue; | ||||||||
1883 | if (MO.isUse()) { | ||||||||
1884 | addRegAndItsAliases(Reg, TRI, Uses); | ||||||||
1885 | } else { | ||||||||
1886 | if (Uses.erase(Reg)) { | ||||||||
1887 | if (Register::isPhysicalRegister(Reg)) { | ||||||||
1888 | for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) | ||||||||
1889 | Uses.erase(*SubRegs); // Use sub-registers to be conservative | ||||||||
1890 | } | ||||||||
1891 | } | ||||||||
1892 | addRegAndItsAliases(Reg, TRI, Defs); | ||||||||
1893 | } | ||||||||
1894 | } | ||||||||
1895 | |||||||||
1896 | return PI; | ||||||||
1897 | } | ||||||||
1898 | |||||||||
1899 | bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) { | ||||||||
1900 | MachineBasicBlock *TBB = nullptr, *FBB = nullptr; | ||||||||
1901 | SmallVector<MachineOperand, 4> Cond; | ||||||||
1902 | if (TII->analyzeBranch(*MBB, TBB, FBB, Cond, true) || !TBB || Cond.empty()) | ||||||||
1903 | return false; | ||||||||
1904 | |||||||||
1905 | if (!FBB) FBB = findFalseBlock(MBB, TBB); | ||||||||
1906 | if (!FBB) | ||||||||
1907 | // Malformed bcc? True and false blocks are the same? | ||||||||
1908 | return false; | ||||||||
1909 | |||||||||
1910 | // Restrict the optimization to cases where MBB is the only predecessor, | ||||||||
1911 | // it is an obvious win. | ||||||||
1912 | if (TBB->pred_size() > 1 || FBB->pred_size() > 1) | ||||||||
1913 | return false; | ||||||||
1914 | |||||||||
1915 | // Find a suitable position to hoist the common instructions to. Also figure | ||||||||
1916 | // out which registers are used or defined by instructions from the insertion | ||||||||
1917 | // point to the end of the block. | ||||||||
1918 | SmallSet<unsigned, 4> Uses, Defs; | ||||||||
1919 | MachineBasicBlock::iterator Loc = | ||||||||
1920 | findHoistingInsertPosAndDeps(MBB, TII, TRI, Uses, Defs); | ||||||||
1921 | if (Loc == MBB->end()) | ||||||||
1922 | return false; | ||||||||
1923 | |||||||||
1924 | bool HasDups = false; | ||||||||
1925 | SmallSet<unsigned, 4> ActiveDefsSet, AllDefsSet; | ||||||||
1926 | MachineBasicBlock::iterator TIB = TBB->begin(); | ||||||||
1927 | MachineBasicBlock::iterator FIB = FBB->begin(); | ||||||||
1928 | MachineBasicBlock::iterator TIE = TBB->end(); | ||||||||
1929 | MachineBasicBlock::iterator FIE = FBB->end(); | ||||||||
1930 | while (TIB != TIE && FIB != FIE) { | ||||||||
1931 | // Skip dbg_value instructions. These do not count. | ||||||||
1932 | TIB = skipDebugInstructionsForward(TIB, TIE); | ||||||||
1933 | FIB = skipDebugInstructionsForward(FIB, FIE); | ||||||||
1934 | if (TIB == TIE || FIB == FIE) | ||||||||
1935 | break; | ||||||||
1936 | |||||||||
1937 | if (!TIB->isIdenticalTo(*FIB, MachineInstr::CheckKillDead)) | ||||||||
1938 | break; | ||||||||
1939 | |||||||||
1940 | if (TII->isPredicated(*TIB)) | ||||||||
1941 | // Hard to reason about register liveness with predicated instruction. | ||||||||
1942 | break; | ||||||||
1943 | |||||||||
1944 | bool IsSafe = true; | ||||||||
1945 | for (MachineOperand &MO : TIB->operands()) { | ||||||||
1946 | // Don't attempt to hoist instructions with register masks. | ||||||||
1947 | if (MO.isRegMask()) { | ||||||||
1948 | IsSafe = false; | ||||||||
1949 | break; | ||||||||
1950 | } | ||||||||
1951 | if (!MO.isReg()) | ||||||||
1952 | continue; | ||||||||
1953 | Register Reg = MO.getReg(); | ||||||||
1954 | if (!Reg) | ||||||||
1955 | continue; | ||||||||
1956 | if (MO.isDef()) { | ||||||||
1957 | if (Uses.count(Reg)) { | ||||||||
1958 | // Avoid clobbering a register that's used by the instruction at | ||||||||
1959 | // the point of insertion. | ||||||||
1960 | IsSafe = false; | ||||||||
1961 | break; | ||||||||
1962 | } | ||||||||
1963 | |||||||||
1964 | if (Defs.count(Reg) && !MO.isDead()) { | ||||||||
1965 | // Don't hoist the instruction if the def would be clobber by the | ||||||||
1966 | // instruction at the point insertion. FIXME: This is overly | ||||||||
1967 | // conservative. It should be possible to hoist the instructions | ||||||||
1968 | // in BB2 in the following example: | ||||||||
1969 | // BB1: | ||||||||
1970 | // r1, eflag = op1 r2, r3 | ||||||||
1971 | // brcc eflag | ||||||||
1972 | // | ||||||||
1973 | // BB2: | ||||||||
1974 | // r1 = op2, ... | ||||||||
1975 | // = op3, killed r1 | ||||||||
1976 | IsSafe = false; | ||||||||
1977 | break; | ||||||||
1978 | } | ||||||||
1979 | } else if (!ActiveDefsSet.count(Reg)) { | ||||||||
1980 | if (Defs.count(Reg)) { | ||||||||
1981 | // Use is defined by the instruction at the point of insertion. | ||||||||
1982 | IsSafe = false; | ||||||||
1983 | break; | ||||||||
1984 | } | ||||||||
1985 | |||||||||
1986 | if (MO.isKill() && Uses.count(Reg)) | ||||||||
1987 | // Kills a register that's read by the instruction at the point of | ||||||||
1988 | // insertion. Remove the kill marker. | ||||||||
1989 | MO.setIsKill(false); | ||||||||
1990 | } | ||||||||
1991 | } | ||||||||
1992 | if (!IsSafe) | ||||||||
1993 | break; | ||||||||
1994 | |||||||||
1995 | bool DontMoveAcrossStore = true; | ||||||||
1996 | if (!TIB->isSafeToMove(nullptr, DontMoveAcrossStore)) | ||||||||
1997 | break; | ||||||||
1998 | |||||||||
1999 | // Remove kills from ActiveDefsSet, these registers had short live ranges. | ||||||||
2000 | for (const MachineOperand &MO : TIB->operands()) { | ||||||||
2001 | if (!MO.isReg() || !MO.isUse() || !MO.isKill()) | ||||||||
2002 | continue; | ||||||||
2003 | Register Reg = MO.getReg(); | ||||||||
2004 | if (!Reg) | ||||||||
2005 | continue; | ||||||||
2006 | if (!AllDefsSet.count(Reg)) { | ||||||||
2007 | continue; | ||||||||
2008 | } | ||||||||
2009 | if (Register::isPhysicalRegister(Reg)) { | ||||||||
2010 | for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) | ||||||||
2011 | ActiveDefsSet.erase(*AI); | ||||||||
2012 | } else { | ||||||||
2013 | ActiveDefsSet.erase(Reg); | ||||||||
2014 | } | ||||||||
2015 | } | ||||||||
2016 | |||||||||
2017 | // Track local defs so we can update liveins. | ||||||||
2018 | for (const MachineOperand &MO : TIB->operands()) { | ||||||||
2019 | if (!MO.isReg() || !MO.isDef() || MO.isDead()) | ||||||||
2020 | continue; | ||||||||
2021 | Register Reg = MO.getReg(); | ||||||||
2022 | if (!Reg || Register::isVirtualRegister(Reg)) | ||||||||
2023 | continue; | ||||||||
2024 | addRegAndItsAliases(Reg, TRI, ActiveDefsSet); | ||||||||
2025 | addRegAndItsAliases(Reg, TRI, AllDefsSet); | ||||||||
2026 | } | ||||||||
2027 | |||||||||
2028 | HasDups = true; | ||||||||
2029 | ++TIB; | ||||||||
2030 | ++FIB; | ||||||||
2031 | } | ||||||||
2032 | |||||||||
2033 | if (!HasDups) | ||||||||
2034 | return false; | ||||||||
2035 | |||||||||
2036 | MBB->splice(Loc, TBB, TBB->begin(), TIB); | ||||||||
2037 | FBB->erase(FBB->begin(), FIB); | ||||||||
2038 | |||||||||
2039 | if (UpdateLiveIns) { | ||||||||
2040 | recomputeLiveIns(*TBB); | ||||||||
2041 | recomputeLiveIns(*FBB); | ||||||||
2042 | } | ||||||||
2043 | |||||||||
2044 | ++NumHoist; | ||||||||
2045 | return true; | ||||||||
2046 | } |
1 | //===- llvm/CodeGen/MachineInstrBundleIterator.h ----------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // Defines an iterator class that bundles MachineInstr. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_CODEGEN_MACHINEINSTRBUNDLEITERATOR_H |
14 | #define LLVM_CODEGEN_MACHINEINSTRBUNDLEITERATOR_H |
15 | |
16 | #include "llvm/ADT/ilist.h" |
17 | #include "llvm/ADT/simple_ilist.h" |
18 | #include <cassert> |
19 | #include <iterator> |
20 | #include <type_traits> |
21 | |
22 | namespace llvm { |
23 | |
24 | template <class T, bool IsReverse> struct MachineInstrBundleIteratorTraits; |
25 | template <class T> struct MachineInstrBundleIteratorTraits<T, false> { |
26 | using list_type = simple_ilist<T, ilist_sentinel_tracking<true>>; |
27 | using instr_iterator = typename list_type::iterator; |
28 | using nonconst_instr_iterator = typename list_type::iterator; |
29 | using const_instr_iterator = typename list_type::const_iterator; |
30 | }; |
31 | template <class T> struct MachineInstrBundleIteratorTraits<T, true> { |
32 | using list_type = simple_ilist<T, ilist_sentinel_tracking<true>>; |
33 | using instr_iterator = typename list_type::reverse_iterator; |
34 | using nonconst_instr_iterator = typename list_type::reverse_iterator; |
35 | using const_instr_iterator = typename list_type::const_reverse_iterator; |
36 | }; |
37 | template <class T> struct MachineInstrBundleIteratorTraits<const T, false> { |
38 | using list_type = simple_ilist<T, ilist_sentinel_tracking<true>>; |
39 | using instr_iterator = typename list_type::const_iterator; |
40 | using nonconst_instr_iterator = typename list_type::iterator; |
41 | using const_instr_iterator = typename list_type::const_iterator; |
42 | }; |
43 | template <class T> struct MachineInstrBundleIteratorTraits<const T, true> { |
44 | using list_type = simple_ilist<T, ilist_sentinel_tracking<true>>; |
45 | using instr_iterator = typename list_type::const_reverse_iterator; |
46 | using nonconst_instr_iterator = typename list_type::reverse_iterator; |
47 | using const_instr_iterator = typename list_type::const_reverse_iterator; |
48 | }; |
49 | |
50 | template <bool IsReverse> struct MachineInstrBundleIteratorHelper; |
51 | template <> struct MachineInstrBundleIteratorHelper<false> { |
52 | /// Get the beginning of the current bundle. |
53 | template <class Iterator> static Iterator getBundleBegin(Iterator I) { |
54 | if (!I.isEnd()) |
55 | while (I->isBundledWithPred()) |
56 | --I; |
57 | return I; |
58 | } |
59 | |
60 | /// Get the final node of the current bundle. |
61 | template <class Iterator> static Iterator getBundleFinal(Iterator I) { |
62 | if (!I.isEnd()) |
63 | while (I->isBundledWithSucc()) |
64 | ++I; |
65 | return I; |
66 | } |
67 | |
68 | /// Increment forward ilist iterator. |
69 | template <class Iterator> static void increment(Iterator &I) { |
70 | I = std::next(getBundleFinal(I)); |
71 | } |
72 | |
73 | /// Decrement forward ilist iterator. |
74 | template <class Iterator> static void decrement(Iterator &I) { |
75 | I = getBundleBegin(std::prev(I)); |
76 | } |
77 | }; |
78 | |
79 | template <> struct MachineInstrBundleIteratorHelper<true> { |
80 | /// Get the beginning of the current bundle. |
81 | template <class Iterator> static Iterator getBundleBegin(Iterator I) { |
82 | return MachineInstrBundleIteratorHelper<false>::getBundleBegin( |
83 | I.getReverse()) |
84 | .getReverse(); |
85 | } |
86 | |
87 | /// Get the final node of the current bundle. |
88 | template <class Iterator> static Iterator getBundleFinal(Iterator I) { |
89 | return MachineInstrBundleIteratorHelper<false>::getBundleFinal( |
90 | I.getReverse()) |
91 | .getReverse(); |
92 | } |
93 | |
94 | /// Increment reverse ilist iterator. |
95 | template <class Iterator> static void increment(Iterator &I) { |
96 | I = getBundleBegin(std::next(I)); |
97 | } |
98 | |
99 | /// Decrement reverse ilist iterator. |
100 | template <class Iterator> static void decrement(Iterator &I) { |
101 | I = std::prev(getBundleFinal(I)); |
102 | } |
103 | }; |
104 | |
105 | /// MachineBasicBlock iterator that automatically skips over MIs that are |
106 | /// inside bundles (i.e. walk top level MIs only). |
107 | template <typename Ty, bool IsReverse = false> |
108 | class MachineInstrBundleIterator : MachineInstrBundleIteratorHelper<IsReverse> { |
109 | using Traits = MachineInstrBundleIteratorTraits<Ty, IsReverse>; |
110 | using instr_iterator = typename Traits::instr_iterator; |
111 | |
112 | instr_iterator MII; |
113 | |
114 | public: |
115 | using value_type = typename instr_iterator::value_type; |
116 | using difference_type = typename instr_iterator::difference_type; |
117 | using pointer = typename instr_iterator::pointer; |
118 | using reference = typename instr_iterator::reference; |
119 | using const_pointer = typename instr_iterator::const_pointer; |
120 | using const_reference = typename instr_iterator::const_reference; |
121 | using iterator_category = std::bidirectional_iterator_tag; |
122 | |
123 | private: |
124 | using nonconst_instr_iterator = typename Traits::nonconst_instr_iterator; |
125 | using const_instr_iterator = typename Traits::const_instr_iterator; |
126 | using nonconst_iterator = |
127 | MachineInstrBundleIterator<typename nonconst_instr_iterator::value_type, |
128 | IsReverse>; |
129 | using reverse_iterator = MachineInstrBundleIterator<Ty, !IsReverse>; |
130 | |
131 | public: |
132 | MachineInstrBundleIterator(instr_iterator MI) : MII(MI) { |
133 | assert((!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred()) &&(((!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred ()) && "It's not legal to initialize MachineInstrBundleIterator with a " "bundled MI") ? static_cast<void> (0) : __assert_fail ( "(!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred()) && \"It's not legal to initialize MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 135, __PRETTY_FUNCTION__)) |
134 | "It's not legal to initialize MachineInstrBundleIterator with a "(((!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred ()) && "It's not legal to initialize MachineInstrBundleIterator with a " "bundled MI") ? static_cast<void> (0) : __assert_fail ( "(!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred()) && \"It's not legal to initialize MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 135, __PRETTY_FUNCTION__)) |
135 | "bundled MI")(((!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred ()) && "It's not legal to initialize MachineInstrBundleIterator with a " "bundled MI") ? static_cast<void> (0) : __assert_fail ( "(!MI.getNodePtr() || MI.isEnd() || !MI->isBundledWithPred()) && \"It's not legal to initialize MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 135, __PRETTY_FUNCTION__)); |
136 | } |
137 | |
138 | MachineInstrBundleIterator(reference MI) : MII(MI) { |
139 | assert(!MI.isBundledWithPred() && "It's not legal to initialize "((!MI.isBundledWithPred() && "It's not legal to initialize " "MachineInstrBundleIterator with a " "bundled MI") ? static_cast <void> (0) : __assert_fail ("!MI.isBundledWithPred() && \"It's not legal to initialize \" \"MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 141, __PRETTY_FUNCTION__)) |
140 | "MachineInstrBundleIterator with a "((!MI.isBundledWithPred() && "It's not legal to initialize " "MachineInstrBundleIterator with a " "bundled MI") ? static_cast <void> (0) : __assert_fail ("!MI.isBundledWithPred() && \"It's not legal to initialize \" \"MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 141, __PRETTY_FUNCTION__)) |
141 | "bundled MI")((!MI.isBundledWithPred() && "It's not legal to initialize " "MachineInstrBundleIterator with a " "bundled MI") ? static_cast <void> (0) : __assert_fail ("!MI.isBundledWithPred() && \"It's not legal to initialize \" \"MachineInstrBundleIterator with a \" \"bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 141, __PRETTY_FUNCTION__)); |
142 | } |
143 | |
144 | MachineInstrBundleIterator(pointer MI) : MII(MI) { |
145 | // FIXME: This conversion should be explicit. |
146 | assert((!MI || !MI->isBundledWithPred()) && "It's not legal to initialize "(((!MI || !MI->isBundledWithPred()) && "It's not legal to initialize " "MachineInstrBundleIterator " "with a bundled MI") ? static_cast <void> (0) : __assert_fail ("(!MI || !MI->isBundledWithPred()) && \"It's not legal to initialize \" \"MachineInstrBundleIterator \" \"with a bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 148, __PRETTY_FUNCTION__)) |
147 | "MachineInstrBundleIterator "(((!MI || !MI->isBundledWithPred()) && "It's not legal to initialize " "MachineInstrBundleIterator " "with a bundled MI") ? static_cast <void> (0) : __assert_fail ("(!MI || !MI->isBundledWithPred()) && \"It's not legal to initialize \" \"MachineInstrBundleIterator \" \"with a bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 148, __PRETTY_FUNCTION__)) |
148 | "with a bundled MI")(((!MI || !MI->isBundledWithPred()) && "It's not legal to initialize " "MachineInstrBundleIterator " "with a bundled MI") ? static_cast <void> (0) : __assert_fail ("(!MI || !MI->isBundledWithPred()) && \"It's not legal to initialize \" \"MachineInstrBundleIterator \" \"with a bundled MI\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/CodeGen/MachineInstrBundleIterator.h" , 148, __PRETTY_FUNCTION__)); |
149 | } |
150 | |
151 | // Template allows conversion from const to nonconst. |
152 | template <class OtherTy> |
153 | MachineInstrBundleIterator( |
154 | const MachineInstrBundleIterator<OtherTy, IsReverse> &I, |
155 | std::enable_if_t<std::is_convertible<OtherTy *, Ty *>::value, void *> = |
156 | nullptr) |
157 | : MII(I.getInstrIterator()) {} |
158 | |
159 | MachineInstrBundleIterator() : MII(nullptr) {} |
160 | |
161 | /// Explicit conversion between forward/reverse iterators. |
162 | /// |
163 | /// Translate between forward and reverse iterators without changing range |
164 | /// boundaries. The resulting iterator will dereference (and have a handle) |
165 | /// to the previous node, which is somewhat unexpected; but converting the |
166 | /// two endpoints in a range will give the same range in reverse. |
167 | /// |
168 | /// This matches std::reverse_iterator conversions. |
169 | explicit MachineInstrBundleIterator( |
170 | const MachineInstrBundleIterator<Ty, !IsReverse> &I) |
171 | : MachineInstrBundleIterator(++I.getReverse()) {} |
172 | |
173 | /// Get the bundle iterator for the given instruction's bundle. |
174 | static MachineInstrBundleIterator getAtBundleBegin(instr_iterator MI) { |
175 | return MachineInstrBundleIteratorHelper<IsReverse>::getBundleBegin(MI); |
176 | } |
177 | |
178 | reference operator*() const { return *MII; } |
179 | pointer operator->() const { return &operator*(); } |
180 | |
181 | /// Check for null. |
182 | bool isValid() const { return MII.getNodePtr(); } |
183 | |
184 | friend bool operator==(const MachineInstrBundleIterator &L, |
185 | const MachineInstrBundleIterator &R) { |
186 | return L.MII == R.MII; |
187 | } |
188 | friend bool operator==(const MachineInstrBundleIterator &L, |
189 | const const_instr_iterator &R) { |
190 | return L.MII == R; // Avoid assertion about validity of R. |
191 | } |
192 | friend bool operator==(const const_instr_iterator &L, |
193 | const MachineInstrBundleIterator &R) { |
194 | return L == R.MII; // Avoid assertion about validity of L. |
195 | } |
196 | friend bool operator==(const MachineInstrBundleIterator &L, |
197 | const nonconst_instr_iterator &R) { |
198 | return L.MII == R; // Avoid assertion about validity of R. |
199 | } |
200 | friend bool operator==(const nonconst_instr_iterator &L, |
201 | const MachineInstrBundleIterator &R) { |
202 | return L == R.MII; // Avoid assertion about validity of L. |
203 | } |
204 | friend bool operator==(const MachineInstrBundleIterator &L, const_pointer R) { |
205 | return L == const_instr_iterator(R); // Avoid assertion about validity of R. |
206 | } |
207 | friend bool operator==(const_pointer L, const MachineInstrBundleIterator &R) { |
208 | return const_instr_iterator(L) == R; // Avoid assertion about validity of L. |
209 | } |
210 | friend bool operator==(const MachineInstrBundleIterator &L, |
211 | const_reference R) { |
212 | return L == &R; // Avoid assertion about validity of R. |
213 | } |
214 | friend bool operator==(const_reference L, |
215 | const MachineInstrBundleIterator &R) { |
216 | return &L == R; // Avoid assertion about validity of L. |
217 | } |
218 | |
219 | friend bool operator!=(const MachineInstrBundleIterator &L, |
220 | const MachineInstrBundleIterator &R) { |
221 | return !(L == R); |
222 | } |
223 | friend bool operator!=(const MachineInstrBundleIterator &L, |
224 | const const_instr_iterator &R) { |
225 | return !(L == R); |
226 | } |
227 | friend bool operator!=(const const_instr_iterator &L, |
228 | const MachineInstrBundleIterator &R) { |
229 | return !(L == R); |
230 | } |
231 | friend bool operator!=(const MachineInstrBundleIterator &L, |
232 | const nonconst_instr_iterator &R) { |
233 | return !(L == R); |
234 | } |
235 | friend bool operator!=(const nonconst_instr_iterator &L, |
236 | const MachineInstrBundleIterator &R) { |
237 | return !(L == R); |
238 | } |
239 | friend bool operator!=(const MachineInstrBundleIterator &L, const_pointer R) { |
240 | return !(L == R); |
241 | } |
242 | friend bool operator!=(const_pointer L, const MachineInstrBundleIterator &R) { |
243 | return !(L == R); |
244 | } |
245 | friend bool operator!=(const MachineInstrBundleIterator &L, |
246 | const_reference R) { |
247 | return !(L == R); |
248 | } |
249 | friend bool operator!=(const_reference L, |
250 | const MachineInstrBundleIterator &R) { |
251 | return !(L == R); |
252 | } |
253 | |
254 | // Increment and decrement operators... |
255 | MachineInstrBundleIterator &operator--() { |
256 | this->decrement(MII); |
257 | return *this; |
258 | } |
259 | MachineInstrBundleIterator &operator++() { |
260 | this->increment(MII); |
261 | return *this; |
262 | } |
263 | MachineInstrBundleIterator operator--(int) { |
264 | MachineInstrBundleIterator Temp = *this; |
265 | --*this; |
266 | return Temp; |
267 | } |
268 | MachineInstrBundleIterator operator++(int) { |
269 | MachineInstrBundleIterator Temp = *this; |
270 | ++*this; |
271 | return Temp; |
272 | } |
273 | |
274 | instr_iterator getInstrIterator() const { return MII; } |
275 | |
276 | nonconst_iterator getNonConstIterator() const { return MII.getNonConst(); } |
277 | |
278 | /// Get a reverse iterator to the same node. |
279 | /// |
280 | /// Gives a reverse iterator that will dereference (and have a handle) to the |
281 | /// same node. Converting the endpoint iterators in a range will give a |
282 | /// different range; for range operations, use the explicit conversions. |
283 | reverse_iterator getReverse() const { return MII.getReverse(); } |
284 | }; |
285 | |
286 | } // end namespace llvm |
287 | |
288 | #endif // LLVM_CODEGEN_MACHINEINSTRBUNDLEITERATOR_H |
1 | //===- llvm/ADT/ilist_iterator.h - Intrusive List Iterator ------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | |
9 | #ifndef LLVM_ADT_ILIST_ITERATOR_H |
10 | #define LLVM_ADT_ILIST_ITERATOR_H |
11 | |
12 | #include "llvm/ADT/ilist_node.h" |
13 | #include <cassert> |
14 | #include <cstddef> |
15 | #include <iterator> |
16 | #include <type_traits> |
17 | |
18 | namespace llvm { |
19 | |
20 | namespace ilist_detail { |
21 | |
22 | /// Find const-correct node types. |
23 | template <class OptionsT, bool IsConst> struct IteratorTraits; |
24 | template <class OptionsT> struct IteratorTraits<OptionsT, false> { |
25 | using value_type = typename OptionsT::value_type; |
26 | using pointer = typename OptionsT::pointer; |
27 | using reference = typename OptionsT::reference; |
28 | using node_pointer = ilist_node_impl<OptionsT> *; |
29 | using node_reference = ilist_node_impl<OptionsT> &; |
30 | }; |
31 | template <class OptionsT> struct IteratorTraits<OptionsT, true> { |
32 | using value_type = const typename OptionsT::value_type; |
33 | using pointer = typename OptionsT::const_pointer; |
34 | using reference = typename OptionsT::const_reference; |
35 | using node_pointer = const ilist_node_impl<OptionsT> *; |
36 | using node_reference = const ilist_node_impl<OptionsT> &; |
37 | }; |
38 | |
39 | template <bool IsReverse> struct IteratorHelper; |
40 | template <> struct IteratorHelper<false> : ilist_detail::NodeAccess { |
41 | using Access = ilist_detail::NodeAccess; |
42 | |
43 | template <class T> static void increment(T *&I) { I = Access::getNext(*I); } |
44 | template <class T> static void decrement(T *&I) { I = Access::getPrev(*I); } |
45 | }; |
46 | template <> struct IteratorHelper<true> : ilist_detail::NodeAccess { |
47 | using Access = ilist_detail::NodeAccess; |
48 | |
49 | template <class T> static void increment(T *&I) { I = Access::getPrev(*I); } |
50 | template <class T> static void decrement(T *&I) { I = Access::getNext(*I); } |
51 | }; |
52 | |
53 | } // end namespace ilist_detail |
54 | |
55 | /// Iterator for intrusive lists based on ilist_node. |
56 | template <class OptionsT, bool IsReverse, bool IsConst> |
57 | class ilist_iterator : ilist_detail::SpecificNodeAccess<OptionsT> { |
58 | friend ilist_iterator<OptionsT, IsReverse, !IsConst>; |
59 | friend ilist_iterator<OptionsT, !IsReverse, IsConst>; |
60 | friend ilist_iterator<OptionsT, !IsReverse, !IsConst>; |
61 | |
62 | using Traits = ilist_detail::IteratorTraits<OptionsT, IsConst>; |
63 | using Access = ilist_detail::SpecificNodeAccess<OptionsT>; |
64 | |
65 | public: |
66 | using value_type = typename Traits::value_type; |
67 | using pointer = typename Traits::pointer; |
68 | using reference = typename Traits::reference; |
69 | using difference_type = ptrdiff_t; |
70 | using iterator_category = std::bidirectional_iterator_tag; |
71 | using const_pointer = typename OptionsT::const_pointer; |
72 | using const_reference = typename OptionsT::const_reference; |
73 | |
74 | private: |
75 | using node_pointer = typename Traits::node_pointer; |
76 | using node_reference = typename Traits::node_reference; |
77 | |
78 | node_pointer NodePtr = nullptr; |
79 | |
80 | public: |
81 | /// Create from an ilist_node. |
82 | explicit ilist_iterator(node_reference N) : NodePtr(&N) {} |
83 | |
84 | explicit ilist_iterator(pointer NP) : NodePtr(Access::getNodePtr(NP)) {} |
85 | explicit ilist_iterator(reference NR) : NodePtr(Access::getNodePtr(&NR)) {} |
86 | ilist_iterator() = default; |
87 | |
88 | // This is templated so that we can allow constructing a const iterator from |
89 | // a nonconst iterator... |
90 | template <bool RHSIsConst> |
91 | ilist_iterator(const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS, |
92 | std::enable_if_t<IsConst || !RHSIsConst, void *> = nullptr) |
93 | : NodePtr(RHS.NodePtr) {} |
94 | |
95 | // This is templated so that we can allow assigning to a const iterator from |
96 | // a nonconst iterator... |
97 | template <bool RHSIsConst> |
98 | std::enable_if_t<IsConst || !RHSIsConst, ilist_iterator &> |
99 | operator=(const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS) { |
100 | NodePtr = RHS.NodePtr; |
101 | return *this; |
102 | } |
103 | |
104 | /// Explicit conversion between forward/reverse iterators. |
105 | /// |
106 | /// Translate between forward and reverse iterators without changing range |
107 | /// boundaries. The resulting iterator will dereference (and have a handle) |
108 | /// to the previous node, which is somewhat unexpected; but converting the |
109 | /// two endpoints in a range will give the same range in reverse. |
110 | /// |
111 | /// This matches std::reverse_iterator conversions. |
112 | explicit ilist_iterator( |
113 | const ilist_iterator<OptionsT, !IsReverse, IsConst> &RHS) |
114 | : ilist_iterator(++RHS.getReverse()) {} |
115 | |
116 | /// Get a reverse iterator to the same node. |
117 | /// |
118 | /// Gives a reverse iterator that will dereference (and have a handle) to the |
119 | /// same node. Converting the endpoint iterators in a range will give a |
120 | /// different range; for range operations, use the explicit conversions. |
121 | ilist_iterator<OptionsT, !IsReverse, IsConst> getReverse() const { |
122 | if (NodePtr) |
123 | return ilist_iterator<OptionsT, !IsReverse, IsConst>(*NodePtr); |
124 | return ilist_iterator<OptionsT, !IsReverse, IsConst>(); |
125 | } |
126 | |
127 | /// Const-cast. |
128 | ilist_iterator<OptionsT, IsReverse, false> getNonConst() const { |
129 | if (NodePtr) |
130 | return ilist_iterator<OptionsT, IsReverse, false>( |
131 | const_cast<typename ilist_iterator<OptionsT, IsReverse, |
132 | false>::node_reference>(*NodePtr)); |
133 | return ilist_iterator<OptionsT, IsReverse, false>(); |
134 | } |
135 | |
136 | // Accessors... |
137 | reference operator*() const { |
138 | assert(!NodePtr->isKnownSentinel())((!NodePtr->isKnownSentinel()) ? static_cast<void> ( 0) : __assert_fail ("!NodePtr->isKnownSentinel()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/ilist_iterator.h" , 138, __PRETTY_FUNCTION__)); |
139 | return *Access::getValuePtr(NodePtr); |
140 | } |
141 | pointer operator->() const { return &operator*(); } |
142 | |
143 | // Comparison operators |
144 | friend bool operator==(const ilist_iterator &LHS, const ilist_iterator &RHS) { |
145 | return LHS.NodePtr == RHS.NodePtr; |
146 | } |
147 | friend bool operator!=(const ilist_iterator &LHS, const ilist_iterator &RHS) { |
148 | return LHS.NodePtr != RHS.NodePtr; |
149 | } |
150 | |
151 | // Increment and decrement operators... |
152 | ilist_iterator &operator--() { |
153 | NodePtr = IsReverse ? NodePtr->getNext() : NodePtr->getPrev(); |
154 | return *this; |
155 | } |
156 | ilist_iterator &operator++() { |
157 | NodePtr = IsReverse ? NodePtr->getPrev() : NodePtr->getNext(); |
158 | return *this; |
159 | } |
160 | ilist_iterator operator--(int) { |
161 | ilist_iterator tmp = *this; |
162 | --*this; |
163 | return tmp; |
164 | } |
165 | ilist_iterator operator++(int) { |
166 | ilist_iterator tmp = *this; |
167 | ++*this; |
168 | return tmp; |
169 | } |
170 | |
171 | /// Get the underlying ilist_node. |
172 | node_pointer getNodePtr() const { return static_cast<node_pointer>(NodePtr); } |
173 | |
174 | /// Check for end. Only valid if ilist_sentinel_tracking<true>. |
175 | bool isEnd() const { return NodePtr ? NodePtr->isSentinel() : false; } |
176 | }; |
177 | |
178 | template <typename From> struct simplify_type; |
179 | |
180 | /// Allow ilist_iterators to convert into pointers to a node automatically when |
181 | /// used by the dyn_cast, cast, isa mechanisms... |
182 | /// |
183 | /// FIXME: remove this, since there is no implicit conversion to NodeTy. |
184 | template <class OptionsT, bool IsConst> |
185 | struct simplify_type<ilist_iterator<OptionsT, false, IsConst>> { |
186 | using iterator = ilist_iterator<OptionsT, false, IsConst>; |
187 | using SimpleType = typename iterator::pointer; |
188 | |
189 | static SimpleType getSimplifiedValue(const iterator &Node) { return &*Node; } |
190 | }; |
191 | template <class OptionsT, bool IsConst> |
192 | struct simplify_type<const ilist_iterator<OptionsT, false, IsConst>> |
193 | : simplify_type<ilist_iterator<OptionsT, false, IsConst>> {}; |
194 | |
195 | } // end namespace llvm |
196 | |
197 | #endif // LLVM_ADT_ILIST_ITERATOR_H |
1 | //===- llvm/ADT/SmallVector.h - 'Normally small' vectors --------*- C++ -*-===// | ||||||||
2 | // | ||||||||
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||||||||
4 | // See https://llvm.org/LICENSE.txt for license information. | ||||||||
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||||||||
6 | // | ||||||||
7 | //===----------------------------------------------------------------------===// | ||||||||
8 | // | ||||||||
9 | // This file defines the SmallVector class. | ||||||||
10 | // | ||||||||
11 | //===----------------------------------------------------------------------===// | ||||||||
12 | |||||||||
13 | #ifndef LLVM_ADT_SMALLVECTOR_H | ||||||||
14 | #define LLVM_ADT_SMALLVECTOR_H | ||||||||
15 | |||||||||
16 | #include "llvm/ADT/iterator_range.h" | ||||||||
17 | #include "llvm/Support/AlignOf.h" | ||||||||
18 | #include "llvm/Support/Compiler.h" | ||||||||
19 | #include "llvm/Support/MathExtras.h" | ||||||||
20 | #include "llvm/Support/MemAlloc.h" | ||||||||
21 | #include "llvm/Support/type_traits.h" | ||||||||
22 | #include "llvm/Support/ErrorHandling.h" | ||||||||
23 | #include <algorithm> | ||||||||
24 | #include <cassert> | ||||||||
25 | #include <cstddef> | ||||||||
26 | #include <cstdlib> | ||||||||
27 | #include <cstring> | ||||||||
28 | #include <initializer_list> | ||||||||
29 | #include <iterator> | ||||||||
30 | #include <memory> | ||||||||
31 | #include <new> | ||||||||
32 | #include <type_traits> | ||||||||
33 | #include <utility> | ||||||||
34 | |||||||||
35 | namespace llvm { | ||||||||
36 | |||||||||
37 | /// This is all the non-templated stuff common to all SmallVectors. | ||||||||
38 | class SmallVectorBase { | ||||||||
39 | protected: | ||||||||
40 | void *BeginX; | ||||||||
41 | unsigned Size = 0, Capacity; | ||||||||
42 | |||||||||
43 | SmallVectorBase() = delete; | ||||||||
44 | SmallVectorBase(void *FirstEl, size_t TotalCapacity) | ||||||||
45 | : BeginX(FirstEl), Capacity(TotalCapacity) {} | ||||||||
46 | |||||||||
47 | /// This is an implementation of the grow() method which only works | ||||||||
48 | /// on POD-like data types and is out of line to reduce code duplication. | ||||||||
49 | void grow_pod(void *FirstEl, size_t MinCapacity, size_t TSize); | ||||||||
50 | |||||||||
51 | public: | ||||||||
52 | size_t size() const { return Size; } | ||||||||
53 | size_t capacity() const { return Capacity; } | ||||||||
54 | |||||||||
55 | LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { return !Size
| ||||||||
56 | |||||||||
57 | /// Set the array size to \p N, which the current array must have enough | ||||||||
58 | /// capacity for. | ||||||||
59 | /// | ||||||||
60 | /// This does not construct or destroy any elements in the vector. | ||||||||
61 | /// | ||||||||
62 | /// Clients can use this in conjunction with capacity() to write past the end | ||||||||
63 | /// of the buffer when they know that more elements are available, and only | ||||||||
64 | /// update the size later. This avoids the cost of value initializing elements | ||||||||
65 | /// which will only be overwritten. | ||||||||
66 | void set_size(size_t N) { | ||||||||
67 | assert(N <= capacity())((N <= capacity()) ? static_cast<void> (0) : __assert_fail ("N <= capacity()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 67, __PRETTY_FUNCTION__)); | ||||||||
68 | Size = N; | ||||||||
69 | } | ||||||||
70 | }; | ||||||||
71 | |||||||||
72 | /// Figure out the offset of the first element. | ||||||||
73 | template <class T, typename = void> struct SmallVectorAlignmentAndSize { | ||||||||
74 | AlignedCharArrayUnion<SmallVectorBase> Base; | ||||||||
75 | AlignedCharArrayUnion<T> FirstEl; | ||||||||
76 | }; | ||||||||
77 | |||||||||
78 | /// This is the part of SmallVectorTemplateBase which does not depend on whether | ||||||||
79 | /// the type T is a POD. The extra dummy template argument is used by ArrayRef | ||||||||
80 | /// to avoid unnecessarily requiring T to be complete. | ||||||||
81 | template <typename T, typename = void> | ||||||||
82 | class SmallVectorTemplateCommon : public SmallVectorBase { | ||||||||
83 | /// Find the address of the first element. For this pointer math to be valid | ||||||||
84 | /// with small-size of 0 for T with lots of alignment, it's important that | ||||||||
85 | /// SmallVectorStorage is properly-aligned even for small-size of 0. | ||||||||
86 | void *getFirstEl() const { | ||||||||
87 | return const_cast<void *>(reinterpret_cast<const void *>( | ||||||||
88 | reinterpret_cast<const char *>(this) + | ||||||||
89 | offsetof(SmallVectorAlignmentAndSize<T>, FirstEl)__builtin_offsetof(SmallVectorAlignmentAndSize<T>, FirstEl ))); | ||||||||
90 | } | ||||||||
91 | // Space after 'FirstEl' is clobbered, do not add any instance vars after it. | ||||||||
92 | |||||||||
93 | protected: | ||||||||
94 | SmallVectorTemplateCommon(size_t Size) | ||||||||
95 | : SmallVectorBase(getFirstEl(), Size) {} | ||||||||
96 | |||||||||
97 | void grow_pod(size_t MinCapacity, size_t TSize) { | ||||||||
98 | SmallVectorBase::grow_pod(getFirstEl(), MinCapacity, TSize); | ||||||||
99 | } | ||||||||
100 | |||||||||
101 | /// Return true if this is a smallvector which has not had dynamic | ||||||||
102 | /// memory allocated for it. | ||||||||
103 | bool isSmall() const { return BeginX == getFirstEl(); } | ||||||||
104 | |||||||||
105 | /// Put this vector in a state of being small. | ||||||||
106 | void resetToSmall() { | ||||||||
107 | BeginX = getFirstEl(); | ||||||||
108 | Size = Capacity = 0; // FIXME: Setting Capacity to 0 is suspect. | ||||||||
109 | } | ||||||||
110 | |||||||||
111 | public: | ||||||||
112 | using size_type = size_t; | ||||||||
113 | using difference_type = ptrdiff_t; | ||||||||
114 | using value_type = T; | ||||||||
115 | using iterator = T *; | ||||||||
116 | using const_iterator = const T *; | ||||||||
117 | |||||||||
118 | using const_reverse_iterator = std::reverse_iterator<const_iterator>; | ||||||||
119 | using reverse_iterator = std::reverse_iterator<iterator>; | ||||||||
120 | |||||||||
121 | using reference = T &; | ||||||||
122 | using const_reference = const T &; | ||||||||
123 | using pointer = T *; | ||||||||
124 | using const_pointer = const T *; | ||||||||
125 | |||||||||
126 | // forward iterator creation methods. | ||||||||
127 | iterator begin() { return (iterator)this->BeginX; } | ||||||||
128 | const_iterator begin() const { return (const_iterator)this->BeginX; } | ||||||||
129 | iterator end() { return begin() + size(); } | ||||||||
130 | const_iterator end() const { return begin() + size(); } | ||||||||
131 | |||||||||
132 | // reverse iterator creation methods. | ||||||||
133 | reverse_iterator rbegin() { return reverse_iterator(end()); } | ||||||||
134 | const_reverse_iterator rbegin() const{ return const_reverse_iterator(end()); } | ||||||||
135 | reverse_iterator rend() { return reverse_iterator(begin()); } | ||||||||
136 | const_reverse_iterator rend() const { return const_reverse_iterator(begin());} | ||||||||
137 | |||||||||
138 | size_type size_in_bytes() const { return size() * sizeof(T); } | ||||||||
139 | size_type max_size() const { return size_type(-1) / sizeof(T); } | ||||||||
140 | |||||||||
141 | size_t capacity_in_bytes() const { return capacity() * sizeof(T); } | ||||||||
142 | |||||||||
143 | /// Return a pointer to the vector's buffer, even if empty(). | ||||||||
144 | pointer data() { return pointer(begin()); } | ||||||||
145 | /// Return a pointer to the vector's buffer, even if empty(). | ||||||||
146 | const_pointer data() const { return const_pointer(begin()); } | ||||||||
147 | |||||||||
148 | reference operator[](size_type idx) { | ||||||||
149 | assert(idx < size())((idx < size()) ? static_cast<void> (0) : __assert_fail ("idx < size()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 149, __PRETTY_FUNCTION__)); | ||||||||
150 | return begin()[idx]; | ||||||||
151 | } | ||||||||
152 | const_reference operator[](size_type idx) const { | ||||||||
153 | assert(idx < size())((idx < size()) ? static_cast<void> (0) : __assert_fail ("idx < size()", "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 153, __PRETTY_FUNCTION__)); | ||||||||
154 | return begin()[idx]; | ||||||||
155 | } | ||||||||
156 | |||||||||
157 | reference front() { | ||||||||
158 | assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 158, __PRETTY_FUNCTION__)); | ||||||||
159 | return begin()[0]; | ||||||||
160 | } | ||||||||
161 | const_reference front() const { | ||||||||
162 | assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 162, __PRETTY_FUNCTION__)); | ||||||||
163 | return begin()[0]; | ||||||||
164 | } | ||||||||
165 | |||||||||
166 | reference back() { | ||||||||
167 | assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 167, __PRETTY_FUNCTION__)); | ||||||||
168 | return end()[-1]; | ||||||||
169 | } | ||||||||
170 | const_reference back() const { | ||||||||
171 | assert(!empty())((!empty()) ? static_cast<void> (0) : __assert_fail ("!empty()" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 171, __PRETTY_FUNCTION__)); | ||||||||
172 | return end()[-1]; | ||||||||
173 | } | ||||||||
174 | }; | ||||||||
175 | |||||||||
176 | /// SmallVectorTemplateBase<TriviallyCopyable = false> - This is where we put method | ||||||||
177 | /// implementations that are designed to work with non-POD-like T's. | ||||||||
178 | template <typename T, bool = is_trivially_copyable<T>::value> | ||||||||
179 | class SmallVectorTemplateBase : public SmallVectorTemplateCommon<T> { | ||||||||
180 | protected: | ||||||||
181 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} | ||||||||
182 | |||||||||
183 | static void destroy_range(T *S, T *E) { | ||||||||
184 | while (S != E) { | ||||||||
185 | --E; | ||||||||
186 | E->~T(); | ||||||||
187 | } | ||||||||
188 | } | ||||||||
189 | |||||||||
190 | /// Move the range [I, E) into the uninitialized memory starting with "Dest", | ||||||||
191 | /// constructing elements as needed. | ||||||||
192 | template<typename It1, typename It2> | ||||||||
193 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { | ||||||||
194 | std::uninitialized_copy(std::make_move_iterator(I), | ||||||||
195 | std::make_move_iterator(E), Dest); | ||||||||
196 | } | ||||||||
197 | |||||||||
198 | /// Copy the range [I, E) onto the uninitialized memory starting with "Dest", | ||||||||
199 | /// constructing elements as needed. | ||||||||
200 | template<typename It1, typename It2> | ||||||||
201 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { | ||||||||
202 | std::uninitialized_copy(I, E, Dest); | ||||||||
203 | } | ||||||||
204 | |||||||||
205 | /// Grow the allocated memory (without initializing new elements), doubling | ||||||||
206 | /// the size of the allocated memory. Guarantees space for at least one more | ||||||||
207 | /// element, or MinSize more elements if specified. | ||||||||
208 | void grow(size_t MinSize = 0); | ||||||||
209 | |||||||||
210 | public: | ||||||||
211 | void push_back(const T &Elt) { | ||||||||
212 | if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity ()), false)) | ||||||||
213 | this->grow(); | ||||||||
214 | ::new ((void*) this->end()) T(Elt); | ||||||||
215 | this->set_size(this->size() + 1); | ||||||||
216 | } | ||||||||
217 | |||||||||
218 | void push_back(T &&Elt) { | ||||||||
219 | if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity ()), false)) | ||||||||
220 | this->grow(); | ||||||||
221 | ::new ((void*) this->end()) T(::std::move(Elt)); | ||||||||
222 | this->set_size(this->size() + 1); | ||||||||
223 | } | ||||||||
224 | |||||||||
225 | void pop_back() { | ||||||||
226 | this->set_size(this->size() - 1); | ||||||||
227 | this->end()->~T(); | ||||||||
228 | } | ||||||||
229 | }; | ||||||||
230 | |||||||||
231 | // Define this out-of-line to dissuade the C++ compiler from inlining it. | ||||||||
232 | template <typename T, bool TriviallyCopyable> | ||||||||
233 | void SmallVectorTemplateBase<T, TriviallyCopyable>::grow(size_t MinSize) { | ||||||||
234 | if (MinSize > UINT32_MAX(4294967295U)) | ||||||||
235 | report_bad_alloc_error("SmallVector capacity overflow during allocation"); | ||||||||
236 | |||||||||
237 | // Always grow, even from zero. | ||||||||
238 | size_t NewCapacity = size_t(NextPowerOf2(this->capacity() + 2)); | ||||||||
239 | NewCapacity = std::min(std::max(NewCapacity, MinSize), size_t(UINT32_MAX(4294967295U))); | ||||||||
240 | T *NewElts = static_cast<T*>(llvm::safe_malloc(NewCapacity*sizeof(T))); | ||||||||
241 | |||||||||
242 | // Move the elements over. | ||||||||
243 | this->uninitialized_move(this->begin(), this->end(), NewElts); | ||||||||
244 | |||||||||
245 | // Destroy the original elements. | ||||||||
246 | destroy_range(this->begin(), this->end()); | ||||||||
247 | |||||||||
248 | // If this wasn't grown from the inline copy, deallocate the old space. | ||||||||
249 | if (!this->isSmall()) | ||||||||
250 | free(this->begin()); | ||||||||
251 | |||||||||
252 | this->BeginX = NewElts; | ||||||||
253 | this->Capacity = NewCapacity; | ||||||||
254 | } | ||||||||
255 | |||||||||
256 | /// SmallVectorTemplateBase<TriviallyCopyable = true> - This is where we put | ||||||||
257 | /// method implementations that are designed to work with POD-like T's. | ||||||||
258 | template <typename T> | ||||||||
259 | class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> { | ||||||||
260 | protected: | ||||||||
261 | SmallVectorTemplateBase(size_t Size) : SmallVectorTemplateCommon<T>(Size) {} | ||||||||
262 | |||||||||
263 | // No need to do a destroy loop for POD's. | ||||||||
264 | static void destroy_range(T *, T *) {} | ||||||||
265 | |||||||||
266 | /// Move the range [I, E) onto the uninitialized memory | ||||||||
267 | /// starting with "Dest", constructing elements into it as needed. | ||||||||
268 | template<typename It1, typename It2> | ||||||||
269 | static void uninitialized_move(It1 I, It1 E, It2 Dest) { | ||||||||
270 | // Just do a copy. | ||||||||
271 | uninitialized_copy(I, E, Dest); | ||||||||
272 | } | ||||||||
273 | |||||||||
274 | /// Copy the range [I, E) onto the uninitialized memory | ||||||||
275 | /// starting with "Dest", constructing elements into it as needed. | ||||||||
276 | template<typename It1, typename It2> | ||||||||
277 | static void uninitialized_copy(It1 I, It1 E, It2 Dest) { | ||||||||
278 | // Arbitrary iterator types; just use the basic implementation. | ||||||||
279 | std::uninitialized_copy(I, E, Dest); | ||||||||
280 | } | ||||||||
281 | |||||||||
282 | /// Copy the range [I, E) onto the uninitialized memory | ||||||||
283 | /// starting with "Dest", constructing elements into it as needed. | ||||||||
284 | template <typename T1, typename T2> | ||||||||
285 | static void uninitialized_copy( | ||||||||
286 | T1 *I, T1 *E, T2 *Dest, | ||||||||
287 | std::enable_if_t<std::is_same<typename std::remove_const<T1>::type, | ||||||||
288 | T2>::value> * = nullptr) { | ||||||||
289 | // Use memcpy for PODs iterated by pointers (which includes SmallVector | ||||||||
290 | // iterators): std::uninitialized_copy optimizes to memmove, but we can | ||||||||
291 | // use memcpy here. Note that I and E are iterators and thus might be | ||||||||
292 | // invalid for memcpy if they are equal. | ||||||||
293 | if (I != E) | ||||||||
294 | memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T)); | ||||||||
295 | } | ||||||||
296 | |||||||||
297 | /// Double the size of the allocated memory, guaranteeing space for at | ||||||||
298 | /// least one more element or MinSize if specified. | ||||||||
299 | void grow(size_t MinSize = 0) { this->grow_pod(MinSize, sizeof(T)); } | ||||||||
300 | |||||||||
301 | public: | ||||||||
302 | void push_back(const T &Elt) { | ||||||||
303 | if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity ()), false)) | ||||||||
304 | this->grow(); | ||||||||
305 | memcpy(reinterpret_cast<void *>(this->end()), &Elt, sizeof(T)); | ||||||||
306 | this->set_size(this->size() + 1); | ||||||||
307 | } | ||||||||
308 | |||||||||
309 | void pop_back() { this->set_size(this->size() - 1); } | ||||||||
310 | }; | ||||||||
311 | |||||||||
312 | /// This class consists of common code factored out of the SmallVector class to | ||||||||
313 | /// reduce code duplication based on the SmallVector 'N' template parameter. | ||||||||
314 | template <typename T> | ||||||||
315 | class SmallVectorImpl : public SmallVectorTemplateBase<T> { | ||||||||
316 | using SuperClass = SmallVectorTemplateBase<T>; | ||||||||
317 | |||||||||
318 | public: | ||||||||
319 | using iterator = typename SuperClass::iterator; | ||||||||
320 | using const_iterator = typename SuperClass::const_iterator; | ||||||||
321 | using reference = typename SuperClass::reference; | ||||||||
322 | using size_type = typename SuperClass::size_type; | ||||||||
323 | |||||||||
324 | protected: | ||||||||
325 | // Default ctor - Initialize to empty. | ||||||||
326 | explicit SmallVectorImpl(unsigned N) | ||||||||
327 | : SmallVectorTemplateBase<T>(N) {} | ||||||||
328 | |||||||||
329 | public: | ||||||||
330 | SmallVectorImpl(const SmallVectorImpl &) = delete; | ||||||||
331 | |||||||||
332 | ~SmallVectorImpl() { | ||||||||
333 | // Subclass has already destructed this vector's elements. | ||||||||
334 | // If this wasn't grown from the inline copy, deallocate the old space. | ||||||||
335 | if (!this->isSmall()) | ||||||||
336 | free(this->begin()); | ||||||||
337 | } | ||||||||
338 | |||||||||
339 | void clear() { | ||||||||
340 | this->destroy_range(this->begin(), this->end()); | ||||||||
341 | this->Size = 0; | ||||||||
342 | } | ||||||||
343 | |||||||||
344 | void resize(size_type N) { | ||||||||
345 | if (N < this->size()) { | ||||||||
346 | this->destroy_range(this->begin()+N, this->end()); | ||||||||
347 | this->set_size(N); | ||||||||
348 | } else if (N > this->size()) { | ||||||||
349 | if (this->capacity() < N) | ||||||||
350 | this->grow(N); | ||||||||
351 | for (auto I = this->end(), E = this->begin() + N; I != E; ++I) | ||||||||
352 | new (&*I) T(); | ||||||||
353 | this->set_size(N); | ||||||||
354 | } | ||||||||
355 | } | ||||||||
356 | |||||||||
357 | void resize(size_type N, const T &NV) { | ||||||||
358 | if (N < this->size()) { | ||||||||
359 | this->destroy_range(this->begin()+N, this->end()); | ||||||||
360 | this->set_size(N); | ||||||||
361 | } else if (N > this->size()) { | ||||||||
362 | if (this->capacity() < N) | ||||||||
363 | this->grow(N); | ||||||||
364 | std::uninitialized_fill(this->end(), this->begin()+N, NV); | ||||||||
365 | this->set_size(N); | ||||||||
366 | } | ||||||||
367 | } | ||||||||
368 | |||||||||
369 | void reserve(size_type N) { | ||||||||
370 | if (this->capacity() < N) | ||||||||
371 | this->grow(N); | ||||||||
372 | } | ||||||||
373 | |||||||||
374 | LLVM_NODISCARD[[clang::warn_unused_result]] T pop_back_val() { | ||||||||
375 | T Result = ::std::move(this->back()); | ||||||||
376 | this->pop_back(); | ||||||||
377 | return Result; | ||||||||
378 | } | ||||||||
379 | |||||||||
380 | void swap(SmallVectorImpl &RHS); | ||||||||
381 | |||||||||
382 | /// Add the specified range to the end of the SmallVector. | ||||||||
383 | template <typename in_iter, | ||||||||
384 | typename = std::enable_if_t<std::is_convertible< | ||||||||
385 | typename std::iterator_traits<in_iter>::iterator_category, | ||||||||
386 | std::input_iterator_tag>::value>> | ||||||||
387 | void append(in_iter in_start, in_iter in_end) { | ||||||||
388 | size_type NumInputs = std::distance(in_start, in_end); | ||||||||
389 | if (NumInputs > this->capacity() - this->size()) | ||||||||
390 | this->grow(this->size()+NumInputs); | ||||||||
391 | |||||||||
392 | this->uninitialized_copy(in_start, in_end, this->end()); | ||||||||
393 | this->set_size(this->size() + NumInputs); | ||||||||
394 | } | ||||||||
395 | |||||||||
396 | /// Append \p NumInputs copies of \p Elt to the end. | ||||||||
397 | void append(size_type NumInputs, const T &Elt) { | ||||||||
398 | if (NumInputs > this->capacity() - this->size()) | ||||||||
399 | this->grow(this->size()+NumInputs); | ||||||||
400 | |||||||||
401 | std::uninitialized_fill_n(this->end(), NumInputs, Elt); | ||||||||
402 | this->set_size(this->size() + NumInputs); | ||||||||
403 | } | ||||||||
404 | |||||||||
405 | void append(std::initializer_list<T> IL) { | ||||||||
406 | append(IL.begin(), IL.end()); | ||||||||
407 | } | ||||||||
408 | |||||||||
409 | // FIXME: Consider assigning over existing elements, rather than clearing & | ||||||||
410 | // re-initializing them - for all assign(...) variants. | ||||||||
411 | |||||||||
412 | void assign(size_type NumElts, const T &Elt) { | ||||||||
413 | clear(); | ||||||||
414 | if (this->capacity() < NumElts) | ||||||||
415 | this->grow(NumElts); | ||||||||
416 | this->set_size(NumElts); | ||||||||
417 | std::uninitialized_fill(this->begin(), this->end(), Elt); | ||||||||
418 | } | ||||||||
419 | |||||||||
420 | template <typename in_iter, | ||||||||
421 | typename = std::enable_if_t<std::is_convertible< | ||||||||
422 | typename std::iterator_traits<in_iter>::iterator_category, | ||||||||
423 | std::input_iterator_tag>::value>> | ||||||||
424 | void assign(in_iter in_start, in_iter in_end) { | ||||||||
425 | clear(); | ||||||||
426 | append(in_start, in_end); | ||||||||
427 | } | ||||||||
428 | |||||||||
429 | void assign(std::initializer_list<T> IL) { | ||||||||
430 | clear(); | ||||||||
431 | append(IL); | ||||||||
432 | } | ||||||||
433 | |||||||||
434 | iterator erase(const_iterator CI) { | ||||||||
435 | // Just cast away constness because this is a non-const member function. | ||||||||
436 | iterator I = const_cast<iterator>(CI); | ||||||||
437 | |||||||||
438 | assert(I >= this->begin() && "Iterator to erase is out of bounds.")((I >= this->begin() && "Iterator to erase is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Iterator to erase is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 438, __PRETTY_FUNCTION__)); | ||||||||
439 | assert(I < this->end() && "Erasing at past-the-end iterator.")((I < this->end() && "Erasing at past-the-end iterator." ) ? static_cast<void> (0) : __assert_fail ("I < this->end() && \"Erasing at past-the-end iterator.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 439, __PRETTY_FUNCTION__)); | ||||||||
440 | |||||||||
441 | iterator N = I; | ||||||||
442 | // Shift all elts down one. | ||||||||
443 | std::move(I+1, this->end(), I); | ||||||||
444 | // Drop the last elt. | ||||||||
445 | this->pop_back(); | ||||||||
446 | return(N); | ||||||||
447 | } | ||||||||
448 | |||||||||
449 | iterator erase(const_iterator CS, const_iterator CE) { | ||||||||
450 | // Just cast away constness because this is a non-const member function. | ||||||||
451 | iterator S = const_cast<iterator>(CS); | ||||||||
452 | iterator E = const_cast<iterator>(CE); | ||||||||
453 | |||||||||
454 | assert(S >= this->begin() && "Range to erase is out of bounds.")((S >= this->begin() && "Range to erase is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("S >= this->begin() && \"Range to erase is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 454, __PRETTY_FUNCTION__)); | ||||||||
455 | assert(S <= E && "Trying to erase invalid range.")((S <= E && "Trying to erase invalid range.") ? static_cast <void> (0) : __assert_fail ("S <= E && \"Trying to erase invalid range.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 455, __PRETTY_FUNCTION__)); | ||||||||
456 | assert(E <= this->end() && "Trying to erase past the end.")((E <= this->end() && "Trying to erase past the end." ) ? static_cast<void> (0) : __assert_fail ("E <= this->end() && \"Trying to erase past the end.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 456, __PRETTY_FUNCTION__)); | ||||||||
457 | |||||||||
458 | iterator N = S; | ||||||||
459 | // Shift all elts down. | ||||||||
460 | iterator I = std::move(E, this->end(), S); | ||||||||
461 | // Drop the last elts. | ||||||||
462 | this->destroy_range(I, this->end()); | ||||||||
463 | this->set_size(I - this->begin()); | ||||||||
464 | return(N); | ||||||||
465 | } | ||||||||
466 | |||||||||
467 | iterator insert(iterator I, T &&Elt) { | ||||||||
468 | if (I == this->end()) { // Important special case for empty vector. | ||||||||
469 | this->push_back(::std::move(Elt)); | ||||||||
470 | return this->end()-1; | ||||||||
471 | } | ||||||||
472 | |||||||||
473 | assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 473, __PRETTY_FUNCTION__)); | ||||||||
474 | assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector." ) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 474, __PRETTY_FUNCTION__)); | ||||||||
475 | |||||||||
476 | if (this->size() >= this->capacity()) { | ||||||||
477 | size_t EltNo = I-this->begin(); | ||||||||
478 | this->grow(); | ||||||||
479 | I = this->begin()+EltNo; | ||||||||
480 | } | ||||||||
481 | |||||||||
482 | ::new ((void*) this->end()) T(::std::move(this->back())); | ||||||||
483 | // Push everything else over. | ||||||||
484 | std::move_backward(I, this->end()-1, this->end()); | ||||||||
485 | this->set_size(this->size() + 1); | ||||||||
486 | |||||||||
487 | // If we just moved the element we're inserting, be sure to update | ||||||||
488 | // the reference. | ||||||||
489 | T *EltPtr = &Elt; | ||||||||
490 | if (I <= EltPtr && EltPtr < this->end()) | ||||||||
491 | ++EltPtr; | ||||||||
492 | |||||||||
493 | *I = ::std::move(*EltPtr); | ||||||||
494 | return I; | ||||||||
495 | } | ||||||||
496 | |||||||||
497 | iterator insert(iterator I, const T &Elt) { | ||||||||
498 | if (I == this->end()) { // Important special case for empty vector. | ||||||||
499 | this->push_back(Elt); | ||||||||
500 | return this->end()-1; | ||||||||
501 | } | ||||||||
502 | |||||||||
503 | assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 503, __PRETTY_FUNCTION__)); | ||||||||
504 | assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector." ) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 504, __PRETTY_FUNCTION__)); | ||||||||
505 | |||||||||
506 | if (this->size() >= this->capacity()) { | ||||||||
507 | size_t EltNo = I-this->begin(); | ||||||||
508 | this->grow(); | ||||||||
509 | I = this->begin()+EltNo; | ||||||||
510 | } | ||||||||
511 | ::new ((void*) this->end()) T(std::move(this->back())); | ||||||||
512 | // Push everything else over. | ||||||||
513 | std::move_backward(I, this->end()-1, this->end()); | ||||||||
514 | this->set_size(this->size() + 1); | ||||||||
515 | |||||||||
516 | // If we just moved the element we're inserting, be sure to update | ||||||||
517 | // the reference. | ||||||||
518 | const T *EltPtr = &Elt; | ||||||||
519 | if (I <= EltPtr && EltPtr < this->end()) | ||||||||
520 | ++EltPtr; | ||||||||
521 | |||||||||
522 | *I = *EltPtr; | ||||||||
523 | return I; | ||||||||
524 | } | ||||||||
525 | |||||||||
526 | iterator insert(iterator I, size_type NumToInsert, const T &Elt) { | ||||||||
527 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() | ||||||||
528 | size_t InsertElt = I - this->begin(); | ||||||||
529 | |||||||||
530 | if (I == this->end()) { // Important special case for empty vector. | ||||||||
531 | append(NumToInsert, Elt); | ||||||||
532 | return this->begin()+InsertElt; | ||||||||
533 | } | ||||||||
534 | |||||||||
535 | assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 535, __PRETTY_FUNCTION__)); | ||||||||
536 | assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector." ) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 536, __PRETTY_FUNCTION__)); | ||||||||
537 | |||||||||
538 | // Ensure there is enough space. | ||||||||
539 | reserve(this->size() + NumToInsert); | ||||||||
540 | |||||||||
541 | // Uninvalidate the iterator. | ||||||||
542 | I = this->begin()+InsertElt; | ||||||||
543 | |||||||||
544 | // If there are more elements between the insertion point and the end of the | ||||||||
545 | // range than there are being inserted, we can use a simple approach to | ||||||||
546 | // insertion. Since we already reserved space, we know that this won't | ||||||||
547 | // reallocate the vector. | ||||||||
548 | if (size_t(this->end()-I) >= NumToInsert) { | ||||||||
549 | T *OldEnd = this->end(); | ||||||||
550 | append(std::move_iterator<iterator>(this->end() - NumToInsert), | ||||||||
551 | std::move_iterator<iterator>(this->end())); | ||||||||
552 | |||||||||
553 | // Copy the existing elements that get replaced. | ||||||||
554 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); | ||||||||
555 | |||||||||
556 | std::fill_n(I, NumToInsert, Elt); | ||||||||
557 | return I; | ||||||||
558 | } | ||||||||
559 | |||||||||
560 | // Otherwise, we're inserting more elements than exist already, and we're | ||||||||
561 | // not inserting at the end. | ||||||||
562 | |||||||||
563 | // Move over the elements that we're about to overwrite. | ||||||||
564 | T *OldEnd = this->end(); | ||||||||
565 | this->set_size(this->size() + NumToInsert); | ||||||||
566 | size_t NumOverwritten = OldEnd-I; | ||||||||
567 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); | ||||||||
568 | |||||||||
569 | // Replace the overwritten part. | ||||||||
570 | std::fill_n(I, NumOverwritten, Elt); | ||||||||
571 | |||||||||
572 | // Insert the non-overwritten middle part. | ||||||||
573 | std::uninitialized_fill_n(OldEnd, NumToInsert-NumOverwritten, Elt); | ||||||||
574 | return I; | ||||||||
575 | } | ||||||||
576 | |||||||||
577 | template <typename ItTy, | ||||||||
578 | typename = std::enable_if_t<std::is_convertible< | ||||||||
579 | typename std::iterator_traits<ItTy>::iterator_category, | ||||||||
580 | std::input_iterator_tag>::value>> | ||||||||
581 | iterator insert(iterator I, ItTy From, ItTy To) { | ||||||||
582 | // Convert iterator to elt# to avoid invalidating iterator when we reserve() | ||||||||
583 | size_t InsertElt = I - this->begin(); | ||||||||
584 | |||||||||
585 | if (I == this->end()) { // Important special case for empty vector. | ||||||||
586 | append(From, To); | ||||||||
587 | return this->begin()+InsertElt; | ||||||||
588 | } | ||||||||
589 | |||||||||
590 | assert(I >= this->begin() && "Insertion iterator is out of bounds.")((I >= this->begin() && "Insertion iterator is out of bounds." ) ? static_cast<void> (0) : __assert_fail ("I >= this->begin() && \"Insertion iterator is out of bounds.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 590, __PRETTY_FUNCTION__)); | ||||||||
591 | assert(I <= this->end() && "Inserting past the end of the vector.")((I <= this->end() && "Inserting past the end of the vector." ) ? static_cast<void> (0) : __assert_fail ("I <= this->end() && \"Inserting past the end of the vector.\"" , "/build/llvm-toolchain-snapshot-11~++20200309111110+2c36c23f347/llvm/include/llvm/ADT/SmallVector.h" , 591, __PRETTY_FUNCTION__)); | ||||||||
592 | |||||||||
593 | size_t NumToInsert = std::distance(From, To); | ||||||||
594 | |||||||||
595 | // Ensure there is enough space. | ||||||||
596 | reserve(this->size() + NumToInsert); | ||||||||
597 | |||||||||
598 | // Uninvalidate the iterator. | ||||||||
599 | I = this->begin()+InsertElt; | ||||||||
600 | |||||||||
601 | // If there are more elements between the insertion point and the end of the | ||||||||
602 | // range than there are being inserted, we can use a simple approach to | ||||||||
603 | // insertion. Since we already reserved space, we know that this won't | ||||||||
604 | // reallocate the vector. | ||||||||
605 | if (size_t(this->end()-I) >= NumToInsert) { | ||||||||
606 | T *OldEnd = this->end(); | ||||||||
607 | append(std::move_iterator<iterator>(this->end() - NumToInsert), | ||||||||
608 | std::move_iterator<iterator>(this->end())); | ||||||||
609 | |||||||||
610 | // Copy the existing elements that get replaced. | ||||||||
611 | std::move_backward(I, OldEnd-NumToInsert, OldEnd); | ||||||||
612 | |||||||||
613 | std::copy(From, To, I); | ||||||||
614 | return I; | ||||||||
615 | } | ||||||||
616 | |||||||||
617 | // Otherwise, we're inserting more elements than exist already, and we're | ||||||||
618 | // not inserting at the end. | ||||||||
619 | |||||||||
620 | // Move over the elements that we're about to overwrite. | ||||||||
621 | T *OldEnd = this->end(); | ||||||||
622 | this->set_size(this->size() + NumToInsert); | ||||||||
623 | size_t NumOverwritten = OldEnd-I; | ||||||||
624 | this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten); | ||||||||
625 | |||||||||
626 | // Replace the overwritten part. | ||||||||
627 | for (T *J = I; NumOverwritten > 0; --NumOverwritten) { | ||||||||
628 | *J = *From; | ||||||||
629 | ++J; ++From; | ||||||||
630 | } | ||||||||
631 | |||||||||
632 | // Insert the non-overwritten middle part. | ||||||||
633 | this->uninitialized_copy(From, To, OldEnd); | ||||||||
634 | return I; | ||||||||
635 | } | ||||||||
636 | |||||||||
637 | void insert(iterator I, std::initializer_list<T> IL) { | ||||||||
638 | insert(I, IL.begin(), IL.end()); | ||||||||
639 | } | ||||||||
640 | |||||||||
641 | template <typename... ArgTypes> reference emplace_back(ArgTypes &&... Args) { | ||||||||
642 | if (LLVM_UNLIKELY(this->size() >= this->capacity())__builtin_expect((bool)(this->size() >= this->capacity ()), false)) | ||||||||
643 | this->grow(); | ||||||||
644 | ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...); | ||||||||
645 | this->set_size(this->size() + 1); | ||||||||
646 | return this->back(); | ||||||||
647 | } | ||||||||
648 | |||||||||
649 | SmallVectorImpl &operator=(const SmallVectorImpl &RHS); | ||||||||
650 | |||||||||
651 | SmallVectorImpl &operator=(SmallVectorImpl &&RHS); | ||||||||
652 | |||||||||
653 | bool operator==(const SmallVectorImpl &RHS) const { | ||||||||
654 | if (this->size() != RHS.size()) return false; | ||||||||
655 | return std::equal(this->begin(), this->end(), RHS.begin()); | ||||||||
656 | } | ||||||||
657 | bool operator!=(const SmallVectorImpl &RHS) const { | ||||||||
658 | return !(*this == RHS); | ||||||||
659 | } | ||||||||
660 | |||||||||
661 | bool operator<(const SmallVectorImpl &RHS) const { | ||||||||
662 | return std::lexicographical_compare(this->begin(), this->end(), | ||||||||
663 | RHS.begin(), RHS.end()); | ||||||||
664 | } | ||||||||
665 | }; | ||||||||
666 | |||||||||
667 | template <typename T> | ||||||||
668 | void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) { | ||||||||
669 | if (this == &RHS) return; | ||||||||
670 | |||||||||
671 | // We can only avoid copying elements if neither vector is small. | ||||||||
672 | if (!this->isSmall() && !RHS.isSmall()) { | ||||||||
673 | std::swap(this->BeginX, RHS.BeginX); | ||||||||
674 | std::swap(this->Size, RHS.Size); | ||||||||
675 | std::swap(this->Capacity, RHS.Capacity); | ||||||||
676 | return; | ||||||||
677 | } | ||||||||
678 | if (RHS.size() > this->capacity()) | ||||||||
679 | this->grow(RHS.size()); | ||||||||
680 | if (this->size() > RHS.capacity()) | ||||||||
681 | RHS.grow(this->size()); | ||||||||
682 | |||||||||
683 | // Swap the shared elements. | ||||||||
684 | size_t NumShared = this->size(); | ||||||||
685 | if (NumShared > RHS.size()) NumShared = RHS.size(); | ||||||||
686 | for (size_type i = 0; i != NumShared; ++i) | ||||||||
687 | std::swap((*this)[i], RHS[i]); | ||||||||
688 | |||||||||
689 | // Copy over the extra elts. | ||||||||
690 | if (this->size() > RHS.size()) { | ||||||||
691 | size_t EltDiff = this->size() - RHS.size(); | ||||||||
692 | this->uninitialized_copy(this->begin()+NumShared, this->end(), RHS.end()); | ||||||||
693 | RHS.set_size(RHS.size() + EltDiff); | ||||||||
694 | this->destroy_range(this->begin()+NumShared, this->end()); | ||||||||
695 | this->set_size(NumShared); | ||||||||
696 | } else if (RHS.size() > this->size()) { | ||||||||
697 | size_t EltDiff = RHS.size() - this->size(); | ||||||||
698 | this->uninitialized_copy(RHS.begin()+NumShared, RHS.end(), this->end()); | ||||||||
699 | this->set_size(this->size() + EltDiff); | ||||||||
700 | this->destroy_range(RHS.begin()+NumShared, RHS.end()); | ||||||||
701 | RHS.set_size(NumShared); | ||||||||
702 | } | ||||||||
703 | } | ||||||||
704 | |||||||||
705 | template <typename T> | ||||||||
706 | SmallVectorImpl<T> &SmallVectorImpl<T>:: | ||||||||
707 | operator=(const SmallVectorImpl<T> &RHS) { | ||||||||
708 | // Avoid self-assignment. | ||||||||
709 | if (this == &RHS) return *this; | ||||||||
710 | |||||||||
711 | // If we already have sufficient space, assign the common elements, then | ||||||||
712 | // destroy any excess. | ||||||||
713 | size_t RHSSize = RHS.size(); | ||||||||
714 | size_t CurSize = this->size(); | ||||||||
715 | if (CurSize >= RHSSize) { | ||||||||
716 | // Assign common elements. | ||||||||
717 | iterator NewEnd; | ||||||||
718 | if (RHSSize) | ||||||||
719 | NewEnd = std::copy(RHS.begin(), RHS.begin()+RHSSize, this->begin()); | ||||||||
720 | else | ||||||||
721 | NewEnd = this->begin(); | ||||||||
722 | |||||||||
723 | // Destroy excess elements. | ||||||||
724 | this->destroy_range(NewEnd, this->end()); | ||||||||
725 | |||||||||
726 | // Trim. | ||||||||
727 | this->set_size(RHSSize); | ||||||||
728 | return *this; | ||||||||
729 | } | ||||||||
730 | |||||||||
731 | // If we have to grow to have enough elements, destroy the current elements. | ||||||||
732 | // This allows us to avoid copying them during the grow. | ||||||||
733 | // FIXME: don't do this if they're efficiently moveable. | ||||||||
734 | if (this->capacity() < RHSSize) { | ||||||||
735 | // Destroy current elements. | ||||||||
736 | this->destroy_range(this->begin(), this->end()); | ||||||||
737 | this->set_size(0); | ||||||||
738 | CurSize = 0; | ||||||||
739 | this->grow(RHSSize); | ||||||||
740 | } else if (CurSize) { | ||||||||
741 | // Otherwise, use assignment for the already-constructed elements. | ||||||||
742 | std::copy(RHS.begin(), RHS.begin()+CurSize, this->begin()); | ||||||||
743 | } | ||||||||
744 | |||||||||
745 | // Copy construct the new elements in place. | ||||||||
746 | this->uninitialized_copy(RHS.begin()+CurSize, RHS.end(), | ||||||||
747 | this->begin()+CurSize); | ||||||||
748 | |||||||||
749 | // Set end. | ||||||||
750 | this->set_size(RHSSize); | ||||||||
751 | return *this; | ||||||||
752 | } | ||||||||
753 | |||||||||
754 | template <typename T> | ||||||||
755 | SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) { | ||||||||
756 | // Avoid self-assignment. | ||||||||
757 | if (this == &RHS) return *this; | ||||||||
758 | |||||||||
759 | // If the RHS isn't small, clear this vector and then steal its buffer. | ||||||||
760 | if (!RHS.isSmall()) { | ||||||||
761 | this->destroy_range(this->begin(), this->end()); | ||||||||
762 | if (!this->isSmall()) free(this->begin()); | ||||||||
763 | this->BeginX = RHS.BeginX; | ||||||||
764 | this->Size = RHS.Size; | ||||||||
765 | this->Capacity = RHS.Capacity; | ||||||||
766 | RHS.resetToSmall(); | ||||||||
767 | return *this; | ||||||||
768 | } | ||||||||
769 | |||||||||
770 | // If we already have sufficient space, assign the common elements, then | ||||||||
771 | // destroy any excess. | ||||||||
772 | size_t RHSSize = RHS.size(); | ||||||||
773 | size_t CurSize = this->size(); | ||||||||
774 | if (CurSize >= RHSSize) { | ||||||||
775 | // Assign common elements. | ||||||||
776 | iterator NewEnd = this->begin(); | ||||||||
777 | if (RHSSize) | ||||||||
778 | NewEnd = std::move(RHS.begin(), RHS.end(), NewEnd); | ||||||||
779 | |||||||||
780 | // Destroy excess elements and trim the bounds. | ||||||||
781 | this->destroy_range(NewEnd, this->end()); | ||||||||
782 | this->set_size(RHSSize); | ||||||||
783 | |||||||||
784 | // Clear the RHS. | ||||||||
785 | RHS.clear(); | ||||||||
786 | |||||||||
787 | return *this; | ||||||||
788 | } | ||||||||
789 | |||||||||
790 | // If we have to grow to have enough elements, destroy the current elements. | ||||||||
791 | // This allows us to avoid copying them during the grow. | ||||||||
792 | // FIXME: this may not actually make any sense if we can efficiently move | ||||||||
793 | // elements. | ||||||||
794 | if (this->capacity() < RHSSize) { | ||||||||
795 | // Destroy current elements. | ||||||||
796 | this->destroy_range(this->begin(), this->end()); | ||||||||
797 | this->set_size(0); | ||||||||
798 | CurSize = 0; | ||||||||
799 | this->grow(RHSSize); | ||||||||
800 | } else if (CurSize) { | ||||||||
801 | // Otherwise, use assignment for the already-constructed elements. | ||||||||
802 | std::move(RHS.begin(), RHS.begin()+CurSize, this->begin()); | ||||||||
803 | } | ||||||||
804 | |||||||||
805 | // Move-construct the new elements in place. | ||||||||
806 | this->uninitialized_move(RHS.begin()+CurSize, RHS.end(), | ||||||||
807 | this->begin()+CurSize); | ||||||||
808 | |||||||||
809 | // Set end. | ||||||||
810 | this->set_size(RHSSize); | ||||||||
811 | |||||||||
812 | RHS.clear(); | ||||||||
813 | return *this; | ||||||||
814 | } | ||||||||
815 | |||||||||
816 | /// Storage for the SmallVector elements. This is specialized for the N=0 case | ||||||||
817 | /// to avoid allocating unnecessary storage. | ||||||||
818 | template <typename T, unsigned N> | ||||||||
819 | struct SmallVectorStorage { | ||||||||
820 | AlignedCharArrayUnion<T> InlineElts[N]; | ||||||||
821 | }; | ||||||||
822 | |||||||||
823 | /// We need the storage to be properly aligned even for small-size of 0 so that | ||||||||
824 | /// the pointer math in \a SmallVectorTemplateCommon::getFirstEl() is | ||||||||
825 | /// well-defined. | ||||||||
826 | template <typename T> struct alignas(alignof(T)) SmallVectorStorage<T, 0> {}; | ||||||||
827 | |||||||||
828 | /// This is a 'vector' (really, a variable-sized array), optimized | ||||||||
829 | /// for the case when the array is small. It contains some number of elements | ||||||||
830 | /// in-place, which allows it to avoid heap allocation when the actual number of | ||||||||
831 | /// elements is below that threshold. This allows normal "small" cases to be | ||||||||
832 | /// fast without losing generality for large inputs. | ||||||||
833 | /// | ||||||||
834 | /// Note that this does not attempt to be exception safe. | ||||||||
835 | /// | ||||||||
836 | template <typename T, unsigned N> | ||||||||
837 | class SmallVector : public SmallVectorImpl<T>, SmallVectorStorage<T, N> { | ||||||||
838 | public: | ||||||||
839 | SmallVector() : SmallVectorImpl<T>(N) {} | ||||||||
840 | |||||||||
841 | ~SmallVector() { | ||||||||
842 | // Destroy the constructed elements in the vector. | ||||||||
843 | this->destroy_range(this->begin(), this->end()); | ||||||||
844 | } | ||||||||
845 | |||||||||
846 | explicit SmallVector(size_t Size, const T &Value = T()) | ||||||||
847 | : SmallVectorImpl<T>(N) { | ||||||||
848 | this->assign(Size, Value); | ||||||||
849 | } | ||||||||
850 | |||||||||
851 | template <typename ItTy, | ||||||||
852 | typename = std::enable_if_t<std::is_convertible< | ||||||||
853 | typename std::iterator_traits<ItTy>::iterator_category, | ||||||||
854 | std::input_iterator_tag>::value>> | ||||||||
855 | SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) { | ||||||||
856 | this->append(S, E); | ||||||||
857 | } | ||||||||
858 | |||||||||
859 | template <typename RangeTy> | ||||||||
860 | explicit SmallVector(const iterator_range<RangeTy> &R) | ||||||||
861 | : SmallVectorImpl<T>(N) { | ||||||||
862 | this->append(R.begin(), R.end()); | ||||||||
863 | } | ||||||||
864 | |||||||||
865 | SmallVector(std::initializer_list<T> IL) : SmallVectorImpl<T>(N) { | ||||||||
866 | this->assign(IL); | ||||||||
867 | } | ||||||||
868 | |||||||||
869 | SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) { | ||||||||
870 | if (!RHS.empty()) | ||||||||
871 | SmallVectorImpl<T>::operator=(RHS); | ||||||||
872 | } | ||||||||
873 | |||||||||
874 | const SmallVector &operator=(const SmallVector &RHS) { | ||||||||
875 | SmallVectorImpl<T>::operator=(RHS); | ||||||||
876 | return *this; | ||||||||
877 | } | ||||||||
878 | |||||||||
879 | SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) { | ||||||||
880 | if (!RHS.empty()) | ||||||||
881 | SmallVectorImpl<T>::operator=(::std::move(RHS)); | ||||||||
882 | } | ||||||||
883 | |||||||||
884 | SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) { | ||||||||
885 | if (!RHS.empty()) | ||||||||
886 | SmallVectorImpl<T>::operator=(::std::move(RHS)); | ||||||||
887 | } | ||||||||
888 | |||||||||
889 | const SmallVector &operator=(SmallVector &&RHS) { | ||||||||
890 | SmallVectorImpl<T>::operator=(::std::move(RHS)); | ||||||||
891 | return *this; | ||||||||
892 | } | ||||||||
893 | |||||||||
894 | const SmallVector &operator=(SmallVectorImpl<T> &&RHS) { | ||||||||
895 | SmallVectorImpl<T>::operator=(::std::move(RHS)); | ||||||||
896 | return *this; | ||||||||
897 | } | ||||||||
898 | |||||||||
899 | const SmallVector &operator=(std::initializer_list<T> IL) { | ||||||||
900 | this->assign(IL); | ||||||||
901 | return *this; | ||||||||
902 | } | ||||||||
903 | }; | ||||||||
904 | |||||||||
905 | template <typename T, unsigned N> | ||||||||
906 | inline size_t capacity_in_bytes(const SmallVector<T, N> &X) { | ||||||||
907 | return X.capacity_in_bytes(); | ||||||||
908 | } | ||||||||
909 | |||||||||
910 | /// Given a range of type R, iterate the entire range and return a | ||||||||
911 | /// SmallVector with elements of the vector. This is useful, for example, | ||||||||
912 | /// when you want to iterate a range and then sort the results. | ||||||||
913 | template <unsigned Size, typename R> | ||||||||
914 | SmallVector<typename std::remove_const<typename std::remove_reference< | ||||||||
915 | decltype(*std::begin(std::declval<R &>()))>::type>::type, | ||||||||
916 | Size> | ||||||||
917 | to_vector(R &&Range) { | ||||||||
918 | return {std::begin(Range), std::end(Range)}; | ||||||||
919 | } | ||||||||
920 | |||||||||
921 | } // end namespace llvm | ||||||||
922 | |||||||||
923 | namespace std { | ||||||||
924 | |||||||||
925 | /// Implement std::swap in terms of SmallVector swap. | ||||||||
926 | template<typename T> | ||||||||
927 | inline void | ||||||||
928 | swap(llvm::SmallVectorImpl<T> &LHS, llvm::SmallVectorImpl<T> &RHS) { | ||||||||
929 | LHS.swap(RHS); | ||||||||
930 | } | ||||||||
931 | |||||||||
932 | /// Implement std::swap in terms of SmallVector swap. | ||||||||
933 | template<typename T, unsigned N> | ||||||||
934 | inline void | ||||||||
935 | swap(llvm::SmallVector<T, N> &LHS, llvm::SmallVector<T, N> &RHS) { | ||||||||
936 | LHS.swap(RHS); | ||||||||
937 | } | ||||||||
938 | |||||||||
939 | } // end namespace std | ||||||||
940 | |||||||||
941 | #endif // LLVM_ADT_SMALLVECTOR_H |